DAY 2 YARN

Question 1

What is the normal boiling point of water in absolute English units?
A. 100
B. 212
C. 373
D. 672

Answer 1

D. 672

Question 2

In this process, air is alternately compressed, cooled, and expanded, each expansion results in a considerable reduction in temperature. At low temperatures, the molecules move more slowly and occupy less space, so the air becomes liquid.

A. Lindé
B. Elliott
C. Claude
D. Kellogg

Answer 2

A. Lindé

Question 3

It is a modified process for production of soda ash that is generally more efficient and more environment-friendly.
A. Haber
B. Collin
C. Solvay
D. LeBlanc

Answer 3

C. Solvay

Question 4

Lime contains about 90% CaO. Percentage CaO present in limestone is about?
A. 25
B. 50
C. 70
D. 80

Answer 4

B. 50

Question 5

It is a thermal process equipment used in canning foods.
A. Retort
B. Steamer
C. Tunnel
D. Pasteurization

Answer 5

A. Retort

Question 6

Which measuring device is best used if a red-hot object does not reach a temperature range of 800-1600°C?
A. Thermocouple
B. Optical pyrometer
C. Photoelectric pyrometer
D. Radiation pyrometer

Answer 6

A. Thermocouple

Question 7

Diatomaceous earth is a/an
A. Explosive
B. Filter aid
C. Filter medium
D. Catalyst

Answer 7

B. Filter aid

Question 8

Which adsorbent is used to decolorize yellow glycerine?
A. silica gel
B. alumina
C. fuller’s earth
D. activated carbon

Answer 8

D. activated carbon

Question 9

Which industry does carbon black is mostly used?
A. Rubber
B. Paint
C. Steel
D. Petroleum

Answer 9

A. Rubber

Question 10

The aim of cracking is to produce _________.
A. gasoline
B. lube oil
C. petroleum
D. coke

Answer 10

A. gasoline

Question 11

Gun powder, which is an explosive comprises of charcoal, sulphur and _________.
A. glycerine
B. saltpeter
C. nitroglycerine
D. dynamite

Answer 11

B. saltpeter

Question 12

Which of the following constituents of a fuel does not contribute to its calorific value on combustion?
A. Hydrogen
B. Sulfur
C. Carbon
D. None of these

Answer 12

D. None of these

Question 13

Which of the following is the main component of coal tars?
A. Phenol
B. Toluene
C. naphthalene
D. benzene

Answer 13

C. naphthalene

Question 14

In flue gas analysis by Orsat’s apparatus, carbon dioxide is absorbed by
A. potassium hydroxide
B. dilute potassium carbonate
C. cuprous chloride
D. alkaline pyragallol solution

Answer 14

A. potassium hydroxide

Question 15

A fuel containing carbon and carbon monoxide (but containing no hydrogen or its compounds) is burnt in pure oxygen at a constant pressure, its gross calorific value as compared to net calorific value will be:
A. more
B. less
C. same
D. data insufficient; can’t be predicted

Answer 15

C. same

Question 16

The gas which contributes maximum to the heating value of natural gas is
A. CO
B. CO2
C. H2
D. CH4

Answer 16

D. CH4

Question 17

For every 10% increase in the excess air, the fuel consumption increases by __________ percent.
A. 0.1
B. 2
C. 5
D. 10

Answer 17

A. 0.1

Question 18

In order to improve the octane number of a fuel, a certain additive is added. However, it was discovered that exposure to exhaust that has this compound can cause paralysis, appetite loss, nervous depression, gastritis, and diarrhea. What is the identity of the compound?
A. ethanol
B. ethylene glycol
C. butanol and wax base
D. tetraethyl lead

Answer 18

D. tetraethyl lead

Question 19

The process employing desorption of the absorbed solute by solvent-washing is called
A. elution
B. osmosis
C. reverse osmosis
D. sublimation

Answer 19

A. elution

Question 20

Solvent lean phase is known as
A. Extract
B. Raffinate
C. Residue
D. None of the mentioned

Answer 20

B. Raffinate

Question 21

Leaching of coarse solid lumps is also termed as
A. Decoction
B. Dissolution
C. Percolation
D. Agitation and settling

Answer 21

C. Percolation

Question 22

Degree of freedom for leaching and solvent extraction process is
A. 1
B. 3
C. 0
D. 2

Answer 22

B. 3

Question 23

Pick out the wrong statement pertaining to leaching.
A. Fine solids cannot be leached in a Pachuka tank
B. Door classifier can be used for leaching of coarse solids
C. Vegedata seeds can be leached in either of Bollman extractor, Rotocel or Kennedy extractor
D. Very high temperature is not needed for the leaching of sugar beet

Answer 23

A. Fine solids cannot be leached in a Pachuka tank

Question 24

36. Bollman extractor
    A. Is a static bed leaching equipment
    B. Is used for extraction of oil from oilseed
    C. Is a centrifugal extractor
    D. Employs only counter-current extraction

Answer 24

B. Is used for extraction of oil from oilseed

Question 25

In order to reduce the time required for the removing solute the sugar beets are cut into slices known as
A. Cossette
B. Mush
C. Consot
D. All of the mentioned

Answer 25

A. Cossette

Question 26

Rose oil is extracted from rose leaves using __________distillation.
A. high pressure
B. low pressure
C. extractive
D. steam

Answer 26

D. steam

Question 27

_________ mixing is applicable for differential contactors.
A. Axial
B. Radial
C. Both axial and radial
D. None of the mentioned

Answer 27

A. Axial

Question 28

All of the following are assumptions in ideal leaching EXCEPT?
A. The inert solid is not dissolved in the solvent.
B. Sufficient contact time is provided so that all solute is dissolved in the solvent.
C. The concentration of solution in the final stage and in the initial stages are equal.
D. The solute is infinitely soluble in solvent.

Answer 28

C. The concentration of solution in the final stage and in the initial stages are equal.

Question 29

Fractional solvent extraction
A. Employs only one solvent
B. Employs two solvents
C. Results in low interfacial tension
D. None of these

Answer 29

B. Employs two solvents

Question 30

Which one of the following devices is not used for both the absorption as well as the liquid-liquid extraction processes?
A. Packed towers
B. Plate towers
C. Spray towers
D. Wetted wall column

Answer 30

D. Wetted wall column

Question 31

In liquid extraction, if the selectivity is unity, then
A. Separation of the constituents is the most effective
B. No separation will occur
C. Amount of solvent required will be minimum
D. Solvent flow rate should be very low

Answer 31

B. No separation will occur

Question 32

The flow of fluid in a packed bed typically follows which characteristic?
A. Cross-flow
B. Laminar behavior
C. Turbulent motion
D. A combination of laminar and turbulent behaviors

Answer 32

D. A combination of laminar and turbulent behaviors

Question 33

In a gas-liquid absorption column, for obtaining the maximum absorption efficiency
A. liquid stream should be distributed uniformly.
B. gas stream should be distributed uniformly.
C. both gas as well as liquid streams should be distributed uniformly.
D. by passing should be completely avoided.

Answer 33

C. both gas as well as liquid streams should be distributed uniformly.

Question 34

When the gas to be dissolved in liquid is a/an __________ then normally co-current adsorber are used.
A. mixture of two gases
B. pure gas
C. ideal gas
D. sparingly soluble gas

Answer 34

B. pure gas

Question 35

For gas absorption, low viscosity solvents are preferred, because of their
A. better flow characteristics.
B. low pumping pressure drop.
C. rapid absorption rates.
D. all (a), (b) and (c).

Answer 35

D. all (a), (b) and (c).

Question 36

A measure of the difficulty of the separation
A. NTU
B. HTU
C. Kya
D. M

Answer 36

A. NTU

Question 37

Absorption factor, for a fixed degree of absorption from a fixed amount of gas should be
A. 1
B. > 1
C. < 1
D. </= 1

Answer 37

B. > 1

Question 38

If mass transfer and surface area are increased, the value of the height unit becomes
A. small
B. infinite
C. zero
D. large

Answer 38

A. small

Question 39

Which of the following provides maximum contact surface for a liquid-vapor system?
A. Packed tower
B. Bubble-cap plate column
C. Sieve-plate column
D. Wetted wall column

Answer 39

A. Packed tower

Question 40

Which of the following gas-liquid contacting devices incurs the least pressure drop for a particular duty?
A. Grid tray tower
B. Perforated tray tower
C. Wetted wall tower
D. Bubble cap tower

Answer 40

D. Bubble cap tower

Question 41

In batch distillation, in order to maintain a constant distillate concentration, the reflux must
A. be slowly increased
B. slowly decreased
C. maintained high for long time
D. none of these

Answer 41

B. slowly decreased

Question 42

Flash distillation is suitable for separating the constituents of a binary system, which
A. Form minimum boiling azeotrope
B. Have very wide boiling points
C. Have very close boiling points
D. Form constant boiling azeotrope

Answer 42

B. Have very wide boiling points

Question 43

In distillation columns, the number of bubble caps per tray primarily depends upon the
A. Allowable liquid velocity
B. Allowable gas velocity
C. Allowable gas and liquid velocities
D. Feed composition

Answer 43

C. Allowable gas and liquid velocities

Question 44

When the feed to a distillation column is a saturated liquid, slope of the feed line is
A. Zero
B. Unity
C. Infinity
D. None of these

Answer 44

C. Infinity

Question 45

Smoker’s equation for the calculation of number of equilibrium stages in a continuous binary distillation column is used, when the
A. Relative volatility is close to one (e.g., separation of close boiling isomers)
B. Feed is not at its bubble point
C. Number of equilibrium stages in only stripping section is to be calculated
D. Number of equilibrium stages required is likely to be very small

Answer 45

A. Relative volatility is close to one (e.g., separation of close boiling isomers)

Question 46

Flooding in a column results due to
A. High pressure drop
B. Low pressure drop
C. Low velocity of the liquid
D. High temperature

Answer 46

A. High pressure drop

Question 47

On moving the feed line (q-line) from saturated liquid feed (vertical position) to saturated vapor feed (horizontal feed), if the slope of both the operating lines are to be increased, then it will result in
A. greater degree of separation with a fixed number of trays
B. increased reboiler load
C. increased reflux ratio
D. None of these.

Answer 47

C. increased reflux ratio

Question 48

In distillation, overhead product contains
A. Only one component
B. Two components
C. Any number of components
D. Only saturated liquid

Answer 48

C. Any number of components

Question 49

Which of the following cannot be the value of absolute pressure of a fluid at any point?
A. 0 bar
B. -1 bar
C. 1.45 bar
D. 24 bar

Answer 49

B. -1 bar

Question 50

Friction factor for fluid flow in pipe does not depend upon the _______.
A. Pipe length
B. Pipe roughness
C. Fluid density & viscosity
D. Mass flow rate of fluid

Answer 50

A. Pipe length

Question 51

. In the complete turbulence zone (in rough pipes), the
A. rough and smooth pipes have the same friction factor.
B. laminar film covers the roughness projections.
C. friction factor depends upon Nre only.
D. friction factor is independent of the relative roughness.

Answer 51

D. friction factor is independent of the relative roughness.

Question 52

In deriving Bernoulli’s equation, the fluid is assumed to be __________.
A. Steady, frictionless, with the density being pressure dependent
B. Uniform, steady, incompressible, along a streamline
C. Incompressible, frictionless, steady, along a streamline
D. None of these

Answer 52

C. Incompressible, frictionless, steady, along a streamline

Question 53

Two fluids are flowing through two similar pipes of the same diameter. The Reynolds Number is the same. For the same flow rate, if the viscosity of a fluid is reduced to half the value of the first fluid, the pressure drop will ________.
A. Increase
B. Decrease
C. Remain unchanged
D. Cannot say

Answer 53

B. Decrease

Question 54

Absolute viscosity of a fluid is a function of the _____ of the fluid.
A. motion
B. pressure & temperature
C. shearing stress
D. both B and C

Answer 54

D. both B and C

Question 55

If three pipes of different diameters, lengths & friction factors are connected in parallel, then
A. Q = Q1 + Q2 + Q3
B. V1 = V2 = V3
C. Q1 = Q2 = Q3
D. fF,1 = fF,2 = fF,3

Answer 55

A. Q = Q1 + Q2 + Q3

Question 56

Which of the following pipe bends will incur the largest head loss?
A. U-bend
B. 30 degree bend
C. 45 degree bend
D. 90 degree bend

Answer 56

A. U-bend

Question 57

A piezometer provided in the pipe measures _______.
A. Dynamic Pressure
B. Static Pressure
C. Friction Factor
D. None of these

Answer 57

B. Static Pressure

Question 58

Hydraulic intensifier is used for increasing the
A. Rate of velocity of liquid supply
B. Rate of flow through delivery pipeline of a pump
C. Intensity of pressure of the liquid
D. Momentum rate through delivery pipe

Answer 58

C. Intensity of pressure of the liquid

Question 59

In centrifugal pumps, when cavitation occurs, the pressure of the impeller eye or vane becomes
A. Less than atmospheric pressure
B. Greater than atmospheric pressure
C. Less than liquid vapor pressure
D. Greater than liquid vapor pressure

Answer 59

C. Less than liquid vapor pressure

Question 60

Which of the following is the most common pump for pumping either raw sewage or sludge?
A. Reciprocating Pump
B. Centrifugal Pump
C. Gear Pump
D. Electromagnetic Pump

Answer 60

A. Reciprocating Pump

Question 61

The net positive suction head (NPSH) of a centrifugal pump is defined as the sum of the ________ and the pressure head at the _________.
A. Discharge minus the vapor pressure of the liquid at discharge temperature
B. Suction minus the vapor pressure of the liquid at suction temperature
C. Discharge
D. Suction

Answer 61

B. Suction minus the vapor pressure of the liquid at suction temperature

Question 62

Surge tanks are provided in high pressure water pipelines to ________.
A. Facilitate easy dismantling of pipeline for cleaning and maintenance
B. Store a definite quantity of water all the time
C. Reduce the water hammer
D. None of the above

Answer 62

C. Reduce the water hammer

Question 63

Screen capacity is not a function of
A. Its openings size
B. Screening mechanism
C. Screening surface
D. Atmospheric humidity

Answer 63

D. Atmospheric humidity

Question 64

Ratio of rate of dissolution of cube to sphere?
A. 1.24
B. 0.54
C. 1.94
D. 1.04

Answer 64

A. 1.24

Question 65

Drag force acting on a body does not depend upon the:
A. Density of the fluid
B. Density of the body
C. Velocity of the body
D. Projected area of the body

Answer 65

B. Density of the body

Question 66

Separation of particles of various sizes, shapes, and densities by allowing them to settle in a fluid is called:
A. Froth flotation
B. Classification
C. Clarification
D. Thickening

Answer 66

B. Classification

Question 67

Which of the following material handling set of equipment is not suitable for moving materials in varying paths?
A. Hand trolley
B. Belt conveyor
C. Crane
D. Truck

Answer 67

B. Belt conveyor

Question 68

When the weight of a ball inside the ball mill is just balanced by the centrifugal force,
A. The ball abandons its circular path for a parabolic path
B. The ball abandons its parabolic path for a circular path
C. The ball continues to move on a circular path
D. The ball continues to move on a parabolic path

Answer 68

A. The ball abandons its circular path for a parabolic path

Question 69

Crushing of mineral particles is accomplished in a cage mill, when one or more alloy steel bars are revolved in opposite directions. A cage mill is a type of
A. Vibratory
B. Impact
C. Roll
D. None of these

Answer 69

B. Impact

Question 70

Liners of a ball mill are never made of
A. Lead
B. Alloy steel
C. Rubber or ceramic material
D. Cast iron

Answer 70

A. Lead

Question 71

Colloidal mills are used for __________ grinding.
A. Coarse
B. Intermediate
C. Fine
D. Ultrafine

Answer 71

D. Ultrafine

Question 72

For sizing of fine materials, the most suitable equipment is _______.
A. Trommel
B. Grizzly Screen
C. Shaking Screen
D. Vibrating screen

Answer 72

D. Vibrating screen

Question 73

Hot, lumpy, and abrasive materials are best transported by using a/an ________ conveyor.
A. Apron
B. Belt
C. Screw
D. Flight

Answer 73

A. Apron

Question 74

What is the main difference between wet granulation and dry granulation process in particle technology?
A. Wet granulation uses a liquid binder while dry granulation uses mechanical pressure
B. Wet granulation uses mechanical pressure while dry granulation uses a liquid binder
C. Wet granulation forms larger particles while dry granulation forms smaller particles
D. Wet granulation forms smaller particles while dry granulation forms larger particles

Answer 74

A. Wet granulation uses a liquid binder while dry granulation uses mechanical pressure

Question 75

Lap joints are preferred for plates having thickness __________ mm.
A. < 12.5
B. > 3
C. > 5
D. 5-10

Answer 75

B. > 3

Question 76

A high vapor velocity is required for high plate efficiency in a sieve plate column. The satisfactory value of operating vapor velocity for design purpose in sieve plate column is about __________ percent of the flooding velocity.
A. 45
B. 60
C. 80
D. 95

Answer 76

C. 80

Question 77

Safety valves are provided in chemical equipment to guard against excessive __________.
A. Pressure
B. Turbulence
C. Noise
D. Temperature

Answer 77

A. Pressure

Question 78

Joint efficiency (J) for a seamless pipe is
A. 1
B. 0.85
C. 1.2
D. < 0.5

Answer 78

A. 1

Question 79

Baffles may be eliminated for
A. low viscosity liquids (< 200 poise)
B. high viscosity liquids (> 600 poise)
C. large diameter tanks
D. none of these

Answer 79

B. high viscosity liquids (> 600 poise)

Question 80

Nominal Pipe Size (NPS) of a pipe is an indication of its _________ diameter.
A. Inner
B. Outer
C. Approximate
D. None of these

Answer 80

C. Approximate

Question 81

The normal range of velocity of steam in pipes is __________ m/s.
A. 0.1 - 0.5
B. 1 - 5
C. 10 - 20
D. 80 - 100

Answer 81

D. 80 - 100

Question 82

Skirt support is the most suitable for supporting _________ vessels.
A. Small horizontal
B. Large horizontal
C. Tall vertical
D. Thick walled

Answer 82

D. Thick walled

Question 83

Wind load consideration in the design of a support can be neglected when the vessel is __________.
A. Short and housed indoor
B. Tall but empty
C. Tall but full of liquid
D. None of these

Answer 83

A. Short and housed indoor

Question 84

Generally, no corrosion allowance in wall thickness of a part is required, when __________.
A. stainless steel is used
B. wall thickness is more than 20 mm
C. wall thickness is more than 30 mm
D. plate carbon steel and cast-iron parts are used

Answer 84

C. wall thickness is more than 30 mm

Question 85

Which of the following filtration equipment is generally the most expensive?
A. tower press
B. AFP
C. HBF
D. Drum

Answer 85

A. tower press

Question 86

In continuous filtration (at a constant pressure drop), filtrate flow rate varies inversely as the
A. Square root of the velocity
B. Square of the viscosity
C. Filtration time only
D. Washing time only

Answer 86

A. Square root of the velocity

Question 87

7. Most rotary vacuum filters are operated at about ___ % of its surface area submerged in the slurry.
   A. 20
   B. 50
   C. 40
   D. 35

Answer 87

D. 35

Question 88

Which of the following is a modified fluidized bed dryer?
A. Batch fluidized bed dryers
B. Hybrid fluidized bed dryer
C. Semi-continuous fluidized bed dryer
D. Plug flow fluidized bed dryer

Answer 88

B. Hybrid fluidized bed dryer

Question 89

Which of the following is an advantage of using centrifugal force in place of gravitational force?
A. Far greater rates of separation
B. Possibility of achieving separations which are either not practically feasible, or actually impossible, in the gravitational field
C. Substantial reduction of the size of the equipment
D. All of the above.

Answer 89

D. All of the above.

Question 90

Where the density difference of the two liquid phases to be separated is very small (as in milk cream separator), the most suitable separator is a:
A. disc bowl centrifuge
B. sharpies supercentrifuge
C. batch basket centrifuge
D. sparkler filter

Answer 90

A. disc bowl centrifuge

Question 91

Given that T1 = 300°C, T2 = 600°C, what happens to the drying slope if T2 becomes 900°C?
A. Increased by 1.5
B. Increased by 2
C. Decrease by 1.5
D. Decrease by 2

Answer 91

B. Increased by 2

Question 92

Wet substance will most likely dry when:
A. air is more humid than substance
B. air is less humid than substance
C. substance is more humid than air
D. substance is less humid than air

Answer 92

B. air is less humid than substance

Question 93

During constant rate drying period, vaporization rate per unit drying surface area:
A. decreases with time
B. increases with time
C. does not change with time
D. does not affect the moisture content of the wet solid.

Answer 93

C. does not change with time

Question 94

Food and pharmaceutical products are commonly dried by _______ drying.
A. Direct
B. Indirect
C. Freeze
D. None of these

Answer 94

C. Freeze

Question 95

It is the process where both mass and heat are transferred from gas to liquid.
A. desorption
B. humidification
C. gas absorption
D. dehumidification

Answer 95

D. dehumidification

Question 96

Desert air coolers being rendered ineffective in rainy season is due to:
A. Low humidity
B. Low temperature
C. High humidity
D. Sunny weather

Answer 96

C. High humidity

Question 97

Air initially at 101.3 kPa and 40°C and with a relative humidity of 50%, is cooled at constant pressure to 30°C. The cooled air has a:
A. Higher dew point
B. Higher absolute (specific) humidity
C. Higher relative humidity
D. Higher wet bulb temperature

Answer 97

C. Higher relative humidity

Question 98

Unsaturated air (with dry and wet bulb temperatures being 35 and 25°C respectively) is passed through water spray chamber maintained at 35°C. The air will be:
A. cooled
B. humidified
C. both (a) & (b)
D. dehumidified

Answer 98

B. humidified

Question 99

A natural draft cooling tower is filled with wooden grids, which covers about _______ percent of the tower height.
A. 10-15
B. 30-40
C. 70-80
D. 90-100

Answer 99

A. 10-15

Question 100

Which of the following decreases during evaporative cooling process with recirculated water supply?
A. Wet bulb temperature
B. Relative humidity
C. Partial pressure of vapor
D. None of these

Answer 100

D. None of these

Question 101

Why do we use more than one type of feeding in an evaporator?
A. To increase the feed efficiency
B. To increase the efficiency of the steam used
C. To decrease the steam consumption per unit mass of feed
D. To increase the steam consumption per unit mass of feed

Answer 101

C. To decrease the steam consumption per unit mass of feed

Question 102

Which type of feeding is supposed to give maximum economy to a particular consumption?
A. Forward feed
B. Backward feed
C. Parallel feed
D. Mixed feed

Answer 102

B. Backward feed

Question 103

Crystallizers are one of the most important setups in industries nowadays. It is solely used to dry a solution to an extent to obtain the crystals of the solute. Which one of the following is the most suitable operation to carry out this process?
A. Forced Circulation
B. Natural Circulation
C. Nucleate Boiling
D. Non-nucleate Boiling

Answer 103

A. Forced Circulation

Question 104

Why don’t we use natural convection for evaporating waste streams, crystallizers, and viscous fluids?
A. Slow process
B. Sedimentation problem
C. Prevents fouling at the heating surface
D. Causes overheating

Answer 104

C. Prevents fouling at the heating surface

Question 105

During crystallization, formation of crystal can occur in ________ solution only.
A. Saturated
B. Supersaturated
C. Undersaturated
D. All of the above

Answer 105

B. Supersaturated

Question 106

Crystal size in a continuous crystallizer depends upon the
A. Rate of heat transfer
B. Degree of turbulence
C. Degree of supersaturation
D. All of the above

Answer 106

D. All of the above

Question 107

Which of the following statements about evaporative crystallization are correct?
Statement 1: The process depends on evaporation of the solvent.
Statement 2: This process does not create vapor or suspension of crystals in mother liquor.
A. True, False
B. True, True
C. False, True
D. False, False

Answer 107

A. True, False

Question 108

What are factors affecting crystallization?
A. Degree of agglomeration
B. Crystal shape
C. Particle size distribution
D. All of the above

Answer 108

D. All of the above

Question 109

. How does concentration affect crystallization?
A. Increase in concentration leads to large crystals
B. Decrease in concentration leads to large crystals
C. Increase in concentration leads to small crystals
D. Decrease in concentration leads to small crystals

Answer 109

A. Increase in concentration leads to large crystals

Question 110

This type of crystallizer provides an effective and inexpensive method of producing slurry in equipment that does not require expensive installation.
A. scraped-surface
B. reaction-type
C. mixed-suspension
D. classified-suspension

Answer 110

A. scraped-surface

Question 111

The overall resistance for heat transfer through a series of flat resistances, is the
A. product
B. sum
C. average
D. logarithmic mean

Answer 111

B. sum

Question 112

Maximum heat transfer rate is obtained in _________ flow.
A. Laminar
B. Turbulent
C. Creeping
D. Transition

Answer 112

B. Turbulent

Question 113

Which of the following must be considered when determining the value of the fouling factor?
A. Characteristic of the fluids
B. Velocity of the fluid with suspended solid
C. Suspended solids in the fluid
D. All of the above.

Answer 113

D. All of the above.

Question 114

In case of heat transfer by conduction in a hollow cylinder, ________ mean area is used to calculate the heat transfer rate.
A. geometric
B. arithmetic
C. logarithmic
D. harmonic

Answer 114

C. logarithmic

Question 115

In case of a multipass shell and tube heat exchanger, providing a baffle on the shell side __________ the heat transfer rate.
A. increases
B. decreases
C. does not affect
D. maintains

Answer 115

A. increases

Question 116

Which is TRUE about a gas that is compressed isothermally?
A. W > 0; Q > 0
B. W < 0; Q < 0
C. W < 0; Q > 0
D. W > 0; Q < 0

Answer 116

D. W > 0; Q < 0

Question 117

For an isothermal reversible compression of an ideal gas
A. Only ΔE = 0
B. Only ΔH =0
C. ΔE = ΔH = 0
D. dQ = dE

Answer 117

C. ΔE = ΔH = 0

Question 118

Which of the following is a state function?
A. Gibbs free energy
B. Helmholtz free energy
C. Internal energy
D. All of the above

Answer 118

D. All of the above

Question 119

Heat of reaction at constant volume is identified with __________ change.
A. enthalpy
B. internal energy
C. either A or B
D. neither A nor B

Answer 119

B. internal energy

Question 120

For which of the following reactions is the change in the enthalpy of the system equal to the change in the internal energy?
A. H2 reacting with O2 to form H2O in a bomb calorimeter.
B. An aqueous solution of HCl reacting with an aqueous solution of NaOH to form an aqueous solution of NaCl and H2 gas.
C. CO2 gas reacting with solid NaOH to form solid NaHCO3.
D. Solid Pb(NO3)2 reacting with solid KI to form solid PbI2 and solid KNO3.

Answer 120

D. Solid Pb(NO3)2 reacting with solid KI to form solid PbI2 and solid KNO3.

Question 121

Which reaction below is the most likely to be endothermic?
A. Mg(s) → Mg(g)
B. Na(s) + Cl(g) → NaCl(s)
C. Na+(aq) + e- → Na(g)
D. H+(aq) + OH-(aq) → H2O(l)

Answer 121

A. Mg(s) → Mg(g)

Question 122

Which of the following is TRUE?
A. Ionization energy is exothermic while electron affinity is endothermic.
B. Ionization energy is endothermic while electron affinity is exothermic.
C. Both ionization energy and electron affinity are exothermic.
D. Both ionization energy and electron affinity are endothermic.

Answer 122

B. Ionization energy is endothermic while electron affinity is exothermic.

Question 123

Which of the following is true for solid/liquid substances at their melting points?
A. ΔG = 0
B. ΔH = 0
C. ΔS = 0
D. both ΔH and ΔS=0

Answer 123

A. ΔG = 0

Question 124

A refrigerator may be termed as a
A. Heat pump
B. Heat engine
C. Carnot engine
D. None of these

Answer 124

A. Heat pump

Question 125

In a vapor compression refrigeration system, elevating the evaporator temperature results in:
A. increased COP
B. decreased COP
C. no change in COP
D. increased or decreased COP, depending on the refrigerant

Answer 125

A. increased COP

Question 126

Which is not accompanied by an increase in entropy of the system?
A. discharging a battery
B. boiling of water at atmospheric temperature
C. very slow expansion of gas into an evacuated flask
D. rapid expansion of gas and recompression to its original state

Answer 126

D. rapid expansion of gas and recompression to its original state

Question 127

For spontaneous changes in an isolated system:
A. dS = 0
B. dS ≤ 0
C. dS > 0
D. dS = Constant

Answer 127

C. dS > 0

Question 128

Consider the reaction A + 2B → 3C. Which of the following statements is TRUE?
A. The reaction is exothermic.
B. The reaction order with respect to A is 1.
C. The rate law depends on the concentration of C.
D. The rate of disappearance of A is a third of the rate of appearance of C.

Answer 128

D. The rate of disappearance of A is a third of the rate of appearance of C.

Question 129

Which statement is TRUE about reaction mechanisms?
A. The overall rate law can be determined from any step in the mechanism.
B. The reaction rate is the rate of the fastest elementary step of the mechanism.
C. The equation for the sum of all elementary steps is the equation of the overall reaction.
D. Species that are produced and consumed in the mechanism act as catalysts for the reaction.

Answer 129

C. The equation for the sum of all elementary steps is the equation of the overall reaction.

Question 130

Even though graphite is thermodynamically more stable than diamond at standard conditions, a diamond will not be converted into graphite over a span of thousands of years. Which explains this?
A. The ∆G for the change from diamond to graphite is greater than zero.
B. The ∆S for the change from diamond to graphite is less than zero.
C. The change from graphite to diamond proceeds relatively faster.
D. The change from diamond to graphite has very large activation energy.

Answer 130

D. The change from diamond to graphite has very large activation energy.

Question 131

The equilibrium constant of chemical reaction __________ in the presence of catalyst.
A. increases
B. decreases
C. remains unaffected
D. can either increase or decrease (depends on the type of catalyst)

Answer 131

C. remains unaffected

Question 132

What type of flow is commonly employ in PFRs?
A. Laminar
B. Transition
C. Turbulent
D. Depends on space time

Answer 132

C. Turbulent

Question 133

Which type of reactor has the same components in it and the outlet stream?
A. CSTR
B. tubular
C. batch
D. plug flow

Answer 133

A. CSTR

Question 134

Space time equals the mean residence time
A. when the density of the reaction mixture is constant.
B. for large diameter tubular reactor.
C. for narrow diameter tubular reactor.
D. for CSTR.

Answer 134

A. when the density of the reaction mixture is constant.

Question 135

For nearly isothermal operation involving large reaction time in a liquid-phase reaction, the most suitable reactor is a
A. stirred tank
B. tubular flow
C. batch
D. fixed bed

Answer 135

A. stirred tank

Question 136

The most suitable reactor for carrying out an auto-thermal reaction is a
A. Batch reactor
B. CSTR
C. Semi-batch reactor
D. Plug-flow reactor

Answer 136

B. CSTR

Question 137

Rate of a chemical reaction is independent of the concentration of the reactants for a
A. zero order
B. third order
C. consecutive
D. none of these reaction.

Answer 137

A. zero order

Question 138

Half-life period of a chemical reaction is proportional to CA^-1, if the reaction is of ________ order.
A. first
B. zero
C. second
D. third

Answer 138

C. second

Question 139

The size of plug flow reactor (PFR) for all positive reaction orders and for any given duty, is that of mixed reactor.
A. greater than
B. equal to
C. smaller than
D. unpredictable from the data

Answer 139

C. smaller than

Question 140

‘N’ plug flow reactors in series with a total volume ‘V’ gives the same conversion as a single plug flow reactor of volume ‘V’ for __________ order reactions.
A. first
B. second
C. third
D. any

Answer 140

D. any

Question 141

Darcy is a unit of:
A. capacitance
B. permittivity
C. luminance
D. permeability

Answer 141

D. permeability

Question 142

Which of the following is FALSE?
A. The atmospheric pressure is always non-negative.
B. The absolute pressure is always non-negative.
C. The vacuum pressure cannot be negative.
D. The gauge pressure is always positive.

Answer 142

D. The gauge pressure is always positive.

Question 143

Which of the following is not an elastic element-pressure monitoring device?
A. Bourdon tube
B. bellows
C. strain gauges
D. diaphragm

Answer 143

C. strain gauges

Question 144

Which of the following thermocouples is incapable of measuring sub-zero temperatures?
A. chromel-alumel
B. iron-constantan
C. platinum-rhodium
D. copper-constantan

Answer 144

C. platinum-rhodium

Question 145

This type of flow meter utilizes the concept of Faraday’s Law.
A. thermal stress
B. ultrasonic
C. magnetic
D. Coriolis

Answer 145

C. magnetic

Question 146

Which property does NOT increase with an increase in temperature?
A. density
B. thermal diffusivity
C. viscosity
D. thermal conductivity

Answer 146

A. density

Question 147

Tumbling is the process of improving the _________ materials.
A. surface cleanliness
B. surface finish
C. creep limit
D. fatigue limit

Answer 147

A. surface cleanliness

Question 148

Consider a gas stream at 15°C and 105 kPa that flows through a duct and contains 1.2% CO2 by volume. Pure CO2 is also supplied in the duct at a rate of 0.0917 m3/min at 7°C and 131 kPa. Upon exiting, the gas contains 3.4% CO2. Assume that the inlet and outlet gas have the same condition. What is the volumetric flow rate of the inlet stream (m3/min)?
A. 4.2
B. 5.2
C. 8.2
D. 8.7

Answer 148

B. 5.2

Question 149

Which of the following is FALSE about the general balance equation?
A. The accumulation term is always positive.
B. The input and output terms are always positive.
C. For a batch process, the accumulation term is not zero.
D. For a continuous process, the generation and consumption terms are not always zero.

Answer 149

A. The accumulation term is always positive.

Question 150

_______ is caused by premature explosion of fuel in the engine. In order to avoid this, the fuel must have a relatively high ________ number.
A. Scaling, octane
B. Scaling, cetane
C. Knocking, octane
D. Knocking, cetane

Answer 150

C. Knocking, octane

Question 151

A cetane number of zero is characterized by which compound?
A. methylnaphthalene
B. n-cetane
C. heptane
D. isooctane

Answer 151

A. methylnaphthalene

Question 152

Ignition of fuel in a diesel is by ___________.
A. spark
B. fuel injection
C. hot compressed air-fuel mixture
D. none of these

Answer 152

C. hot compressed air-fuel mixture

Question 153

Which of the following is FALSE?
A. Main constituents of LPG are propane and butane.
B. CV of natural gas is about 10000 kcal/Nm³
C. CV of LPG is about 26000 kcal/Nm³
D. LPG is lighter than air

Answer 153

D. LPG is lighter than air

Question 154

Supply of excess air for complete combustion of fuel is needed to facilitate which of the following?
A. its thorough mixing of air
B. achieving equilibrium
C. reaching high temperature
D. none of these

Answer 154

A. its thorough mixing of air

Question 155

What is the air to fuel weight ratio when methane is burnt using theoretical air?
A. 2:1
B. 10:1
C. 17:1
D. 29:1

Answer 155

C. 17:1

Question 156

A coal sample (CV: 32.5 MJ/kg) has 22% VCM, 64% FC, 4% M, 1.4% N, and 1.6% S. It is burned using dry excess air at 28 °C and 1 atm. The stack gas that leaves at 250 °C, 740 mmHg and contains 8.37% CO2, 4.19% CO, and 2.51% H2. What is the mol of dry stack gas for a 100 kg fuel?
A. 23.2
B. 36.3
C. 47.4
D. 52.5

Answer 156

D. 52.5

Question 157

A coal sample (CV: 32.5 MJ/kg) has 22% VCM, 64% FC, 4% M, 1.4% N, and 1.6% S. It is burned using dry excess air at 28 °C and 1 atm. The stack gas that leaves at 250 °C, 740 mmHg and contains 8.37% CO2, 4.19% CO, and 2.51% H2. What is the percent excess oxygen?
A. 30
B. 40
C. 50
D. 60

Answer 157

B. 40

Question 158

A gas sample does 150 kJ of work and at the same time releases 90 kJ of internal energy. How much heat is absorbed/released by the gas?
A. 60 kJ released
B. 60 kJ absorbed
C. 240 kJ released
D. 240 kJ absorbed

Answer 158

B. 60 kJ absorbed

Question 159

What is the change in internal energy (J/mol) of an ideal gas when temperature is increased from 10 to 20 degrees Celsius?
A. 0.5Cv
B. 0.5Cp
C. 10Cv
D. 10Cp

Answer 159

C. 10Cv

Question 160

Which of the following is FALSE about a bomb calorimeter?
A. The heat is equivalent to ΔH.
B. It operates at isochoric condition.
C. It can withstand combustion reactions.
D. All of the statements are true.

Answer 160

A. The heat is equivalent to ΔH.

Question 161

An irreversible process ________________.
A. is the analog of frictionless motion in machines
B. is an idealized visualization of behavior of a system
C. yields the maximum amount of work
D. yields an amount of work less than that of a reversible process

Answer 161

D. yields an amount of work less than that of a reversible process

Question 162

Which of the following is FALSE about the change in enthalpy of a gas at isobaric condition?
A. The value is positive if ΔU is positive and if the volume is increased.
B. The value is positive if ΔU is positive if the temperature is increased.
C. The value is negative if ΔU is negative and if the volume is decreased at high P.
D. All statements are true.

Answer 162

D. All statements are true.

Question 163

A 100 g ice cube at 0°C is dropped in a kilogram of water at 20°C. Assuming there is no heat transfer with the atmosphere, what is the final temperature of the initial water-ice mixture?
A. 0°C
B. 2°C
C. 11°C
D. 12°C

Answer 163

C. 11°C

Question 164

A 900-g ball, initially at 120°C, is submerged in 250 g of water at 20°C and kept inside a coffee-cup calorimeter with a calorimeter constant of 160 J/K. If the temperature of the water rose by 25°C, what is the heat capacity (J/gK) of the ball?
A. 0.39
B. 0.45
C. 0.77
D. 0.83

Answer 164

B. 0.45

Question 165

An isolated system is in equilibrium if the entropy has reached its _________.
A. minimum
B. zero
C. maximum
D. none of these

Answer 165

C. maximum

Question 166

The temperature of the system increases in an ___________ process.
A. isothermal compression
B. isothermal expansion
C. adiabatic expansion
D. adiabatic compression

Answer 166

A. isothermal compression

Question 167

A ton of refrigeration is equivalent to heat removal of ___________.
A. 50 kcal/h
B. 200 BTU/h
C. 200 BTU/min
D. 200 BTU/day

Answer 167

C. 200 BTU/min

Question 168

Calculate the ΔG when a mol of an ideal gas is expanded twice its volume at constant temperature.
A. R ln 0.5
B. R ln 2
C. RT ln 0.5
D. RT ln 2

Answer 168

C. RT ln 0.5

Question 169

Which of the following cycles has two isobaric steps?
A. Otto
B. Diesel
C. Stirling
D. Ericsson

Answer 169

D. Ericsson

Question 170

In which cycle is heat added at constant temperature?
A. Rankine
B. Diesel
C. Brayton
D. Stirling

Answer 170

D. Stirling

Question 171

A nozzle is a device which _________.
A. increases kinetic energy and decreases pressure
B. reduces both kinetic energy and pressure
C. reduces kinetic energy and increases pressure
D. increases both kinetic energy and pressure

Answer 171

A. increases kinetic energy and decreases pressure

Question 172

Adiabatic compression of saturated water vapor makes it __________.
A. supersaturated
B. superheated
C. both A and B
D. neither A nor B

Answer 172

B. superheated

Question 173

Which of the following refrigeration cycles has the minimum COP?
A. air cycle
B. Carnot cycle
C. ordinary vapor compression cycle
D. vapor compression cycle with a reversible expansion engine

Answer 173

A. air cycle

Question 174

For a gaseous system in a closed container, which condition will increase the reaction rate?
A. heat the container
B. introduce a catalyst poison
C. increasing the volume of the container
D. lowering the number of gaseous particles

Answer 174

A. heat the container

Question 175

Consider the conversion of ozone to oxygen using chlorine. What are the reaction orders with respect to chlorine and ozone, respectively?
A. 1/2, 3/2
B. 1,2
C. 3/2, 1/2
D. 2,1

Answer 175

A. 1/2, 3/2

Question 176

In a first order reaction, which reaction characteristic varies as the reaction progresses?
A. half-life
B. rate law
C. rate constant
D. reaction rate

Answer 176

D. reaction rate

Question 177

The concentration of A in a first order reaction A → B, decreases _________ as the reaction progresses.
A. linearly with time.
B. exponentially with time.
C. very abruptly towards the end of the reaction.
D. logarithmically with time.

Answer 177

B. exponentially with time.

Question 178

The half-life of a first order reaction is __________ the initial concentration of the reactant.
A. directly proportional to
B. inversely proportional to
C. independent of
D. none of these

Answer 178

C. independent of

Question 179

Consider the proposed mechanism for the acidic hydrolysis of an ester. Which of the following species is considered as an intermediate?
RCOOR’ + H3O+ → RCOHOR’+ + H2O
RCOHOR’+ + H2O → RC(OH)OR’(OH2)+
RC(OH)OR’(OH2)+ + H20 → RCOOH + R’OH + H3O+
A. RCOHOR’+
B. H3O+
C. RCOOR’
D. R’OH

Answer 179

A. RCOHOR’+

Question 180

While holding other factors as constant, what happens to the instantaneous conversion as time progresses if the reaction order is greater or equal to one?
A. increases constantly
B. increases at first then plateaus
C. decreases constantly
D. decreases at first then plateaus

Answer 180

B. increases at first then plateaus

Question 181

What happens to the fractional conversion of a first order reaction as the initial concentration increases?
A. increases
B. decreases
C. remains constant
D. unpredictable

Answer 181

C. remains constant

Question 182

For the same conversion of reactant A into products, which of the following is FALSE?
A. The reactor volume of PFR is less than that of the CSTR.
B. The residence time using PFR is less than that of the CSTR.
C. The area under the 1/r against C curve for PFR is the residence time.
D. The area under the 1/r against C curve for CSTR is the residence time.

Answer 182

D. The area under the 1/r against C curve for CSTR is the residence time.

Question 183

The buoyant force exerted on an object immersed in fluid is equivalent to __________.
A. Weight of the object
B. Volume of the fluid displaced by the object
C. Weight of the fluid displaced by the object
D. Volume of the object

Answer 183

C. Weight of the fluid displaced by the object

Question 184

Water flowing from a large vessel through a sharp-edged entrance into a pipe will have _________.
A. Friction loss due to contraction
B. Friction loss due to expansion
C. Negligible friction loss
D. Friction loss due to straight pipe

Answer 184

A. Friction loss due to contraction

Question 185

Processes with _________ have great risk of cavitation.
A. high fluid temperature
B. high density
C. low fluid temperature
D. low density

Answer 185

A. high fluid temperature

Question 186

What is the approximate value of the Fanning friction factor for smooth pipe at a Reynolds number equivalent to 1,000,000?
A. 0.3
B. 0.1
C. 0.01
D. 0.003

Answer 186

D. 0.003

Question 187

Streamlines, streamlines, and pathlines are identical under _________ condition.
A. transition flow
B. steady flow
C. isobaric flow
D. isothermal flow

Answer 187

B. steady flow

Question 188

Fitting that will add the least amount of pressure drop in a pipe system.
A. Elbow
B. Coupling
C. Tee
D. Gate Valve

Answer 188

B. Coupling

Question 189

The drag coefficient of a spherical particle, under laminar conditions, is _________.
A. directly proportional to fluid velocity
B. inversely proportional to viscosity
C. directly proportional to fluid density
D. inversely proportional to particle Re

Answer 189

D. inversely proportional to particle Re

Question 190

Water hammer in a pipeline results from the _________.
A. bursting of pipelines due to closure by a valve
B. rapid pressure change due to a rapid change in the rate of flow
C. pressure increase due to closure of a valve resulting in decrease in rate of flow
D. none of these

Answer 190

B. rapid pressure change due to a rapid change in the rate of flow

Question 191

What will happen to a system if the actual NPSH is greater than the required NPSH?
A. Flow in the pipeline will remain stable.
B. Pressure will increase causing the pipe to burst.
C. Fluid will solidify due to abrupt temperature gradient phenomena.
D. Flash bubbles will form and damage the pump

Answer 191

A. Flow in the pipeline will remain stable.

Question 192

Given the flow-rate requirement of a process, more often, the best size of pipe to choose is the one that is:
A. more aesthetic
B. more economical
C. least corrosion resistant
D. least expensive

Answer 192

B. more economical

Question 193

To deliver 100 gpm of water from a reservoir to a storage tank at a head of 3000 ft, what pump must be used?
A. Regenerative
B. Centrifugal-Multistage
C. Centrifugal-Single
D. Axial Flow

Answer 193

B. Centrifugal-Multistage

Question 194

What do you call the friction due to an unseparated boundary layer?
A. Form friction
B. Skin friction
C. Rough friction
D. Streamlined friction

Answer 194

B. Skin friction

Question 195

Select the wrong statement pertaining to the flow of an incompressible fluid through a venturi meter.
A. Venturi meter incurs less power loss compared to an equivalent orifice meter.
B. Discharge of fluid through a venturi meter depends upon the gauge difference irrespective of the orientation of venturi meter.
C. For frictionless flow, the fluid pressure entering the venturi meter will be exactly equal to that leaving the venturi meter.
D. Venturi meter occupies less space than an orifice meter.

Answer 195

D. Venturi meter occupies less space than an orifice meter.

Question 196

The velocity profile for turbulent flow through a closed conduit is:
A. Logarithmic
B. Parabolic
C. Hyperbolic
D. Linear

Answer 196

A. Logarithmic

Question 197

Shear stress in a fluid flowing in a round pipe:
A. varies parabolically across the cross-section
B. remains constant over the cross-section
C. is 0 at the center and varies linearly with the radius
D. is 0 at the wall and increases linearly to the center

Answer 197

C. is 0 at the center and varies linearly with the radius

Question 198

Fluids whose flow behavior show an increase in apparent viscosity with increasing shear rate has a power law equation with what value of n?
A. n=1
B. n>1
C. n<1
D. n=0

Answer 198

B. n>1

Question 199

Diffusion that takes place in fluid phases by physical mixing and by eddies of turbulent flow is called:
A. eddy diffusion
B. forced diffusion
C. thermal diffusion
D. reversed diffusion

Answer 199

A. eddy diffusion

Question 200

Component A is diffusing in a medium B. The flux NA relative to a stationary point is equal to the flux due to molecular diffusion, if
A. Mass transfer is accompanied by reaction
B. diffusion of A is in stagnant medium B
C. molecular mean free path is high
D. there is equimolar counter diffusion

Answer 200

D. there is equimolar counter diffusion

Question 201

Experimental determination of mass transfer coefficient is done using ____________.
A. wetted wall column method
B. inclined plate method
C. spinning disk method
D. parabolic velocity method

Answer 201

A. wetted wall column method

Question 202

Penetration theory relates the average mass transfer coefficient with diffusivity as:
A. K ∝ D
B. K ∝ D^1/2
C. K ∝ D^2
D. K ∝ D^3/2

Answer 202

B. K ∝ D^1/2

Question 203

For laminar flow, the Reynolds analogy is exact if:
A. pressure gradient equals zero.
B. Schmidt number equals one.
C. Prandtl number equals one.
D. All of the above.

Answer 203

D. All of the above.

Question 204

When a drop of blue liquid is added to a cup of water then mixed using a spoon, what type of mass transfer occurs?
A. molecular diffusion
B. convective mass transfer
C. thermal diffusion
D. both A and B

Answer 204

D. both A and B

Question 205

Resistance and conductance depend on:
A. conductivity
B. dimensions of the solid
C. temperature gradient
D. both A and B

Answer 205

D. both A and B

Question 206

Steady state one-dimensional heat flow by conduction as given by Fourier’s law does not assume that:
A. There is no internal heat generation
B. Boundary surfaces are isothermal
C. Material is anisotropic
D. Constant temperature gradient exists

Answer 206

C. Material is anisotropic

Question 207

In cases where there is a multilayer wall of more than one material present in series, the total resistance of the system is:
A. the difference of the resistance of the two outer materials
B. the reciprocal of the highest resistance among the materials
C. the sum of the individual resistances of the materials in series
D. the sum of the reciprocal of the individual resistances of the materials in series

Answer 207

C. the sum of the individual resistances of the materials in series

Question 208

A wall has two layers of materials A and B, each made of a different material. Both the layers have the same thickness. The thermal conductivity of material A is twice that of B. Under the equilibrium, the temperature difference across the layer A is:
A. 6°C
B. 12°C
C. 18°C
D. 24°C

Answer 208

B. 12°C

Question 209

When a system considers very thick-walled cylinders, use the ____ mean radius in computing for heat flow.
A. arithmetic
B. logarithmic
C. geometric
D. either b or c

Answer 209

B. logarithmic

Question 210

Given the same flow rates, inlet and outlet temperatures and heat transfer coefficient, which of the following is TRUE?
A. Parallel flow is more preferred due to smaller area requirement.
B. Countercurrent flow is more preferred due to smaller area requirement.
C. Either parallel or countercurrent flow is desirable since both will require equal areas.
D. All of the above.

Answer 210

B. Countercurrent flow is more preferred due to smaller area requirement.

Question 211

If the baffle spacing in a shell and tube heat exchanger increases, then the Reynolds number of the shell side fluid:
A. Remains unchanged
B. Increases
C. Increases or decreases depending on number of shell passes
D. Decreases

Answer 211

D. Decreases

Question 212

In a multipass shell and tube heat exchanger, tube side return pressure loss is equal to _____ the velocity head.
A. twice
B. half
C. square of
D. four times

Answer 212

D. four times

Question 213

In a heat exchanger, floating head and baffles are provided to _____ and _____ respectively.
A. easily clean the exchanger; relieve stresses caused by thermal expansion
B. relieve stresses caused by thermal expansion; enhance turbulence
C. increase the driving force of heat transfer; easily clean the exchanger
D. enhance turbulence; increase the heat transfer area

Answer 213

B. relieve stresses caused by thermal expansion; enhance turbulence

Question 214

Heat transfer co-efficient equation for forced convection, Nu = 0.023Re^0.8Pr^n, is not valid, if the value of:
A. n = 0.4 is used for heating
B. n = 0.3 is used for cooling
C. Reynolds number for the flow involved is > 10000
D. Reynolds number for the flow involved is < 2100

Answer 214

D. Reynolds number for the flow involved is < 2100

Question 215

In which of the following should fouling factor must be included in the calculation of overall heat transfer coefficient?
A. The liquid contains suspended solids and flows at high velocity
B. The liquid is highly viscous
C. The liquid contains suspended solids and flows at low velocity
D. The liquid has high specific gravity

Answer 215

C. The liquid contains suspended solids and flows at low velocity

Question 216

Which of the following is TRUE?
A. High-pressure liquid should be placed on the shell side of an S&T heat exchanger.
B. Corrosive fluid should be placed on the shell side of an S&T heat exchanger.
C. Fouling fluid should be place on the shell side of an S&T heat exchanger.
D. None of the above.

Answer 216

D. None of the above.

Question 217

Which of the following statements is TRUE?
A. Planck’s Law relates the monochromatic emissive power at a certain temperature and certain wavelength.
B. The wavelength at which the blackbody emissive power is a maximum is derived from integrating Planck’s Law.
C. The total amount of radiation per unit area leaving a surface with a certain temperature over all wavelengths is derived from differentiating Planck’s Law.
D. None of the above.

Answer 217

A. Planck’s Law relates the monochromatic emissive power at a certain temperature and certain wavelength.

Question 218

Which of the following is NOT a property of a black body?
A. α = 1.0
B. ε = 1.0
C. ρ = 0
D. k = 0

Answer 218

D. k = 0

Question 219

In the electromagnetic spectrum, the wavelength range of 10^-13 to 10^-10 m is
A. cosmic ray
B. gamma ray
C. thermal radiation
D. visible radiation

Answer 219

B. gamma ray

Question 220

According to Kirchhoff’s Law, for a gray body, the ______ and __________ are equal even if the body is not in thermal equilibrium with its surroundings.
A. absorptivity, reflectivity
B. absorptivity, emissivity
C. emissivity, thermal conductivity
D. reflectivity, thermal conductivity

Answer 220

B. absorptivity, emissivity

Question 221

This law states that the total emissive power is the total amount of radiation energy per unit area leaving a surface with temperature, T over all wavelengths:
A. Kick’s Law
B. Planck’s Law
C. Kirchhoff’s Law
D. Stefan Boltzmann Law

Answer 221

D. Stefan Boltzmann Law

Question 222

Which of the following is TRUE?
A. Total emissive power increases as temperature increases.
B. Total emissive power decreases as temperature increases.
C. Total emissive power increases as temperature increases to a certain point, then decreases.
D. Total emissive power decreases as temperature increases to a certain point, then increases.

Answer 222

A. Total emissive power increases as temperature increases.

Question 223

What is the value of Stefan Boltzmann constant in SI units?
A. 5.67 x 10^-8
B. 5.67 x 10^-4
C. 0.1713 x 10^-8
D. 0.1713 x 10^-4

Answer 223

A. 5.67 x 10^-8

Question 224

The amount of water evaporated in kg per kg of fuel burnt in a boiler is called the:
A. evaporative capacity
B. evaporative efficiency
C. thermal efficiency
D. steam load

Answer 224

A. evaporative capacity

Question 225

When vaporization takes place directly at the heating surface, it is called:
A. film boiling
B. nucleate boiling
C. vapor binding
D. none of these

Answer 225

B. nucleate boiling

Question 226

Steam is routed through the tubes in the case of a ___________ evaporator.
A. basket-type
B. horizontal tube
C. short tube vertical
D. long tube vertical

Answer 226

B. horizontal tube

Question 227

Which of the following is most suitable for cold viscous feed?
A. Forward feed
B. Backward feed
C. Mixed feed
D. Parallel feed

Answer 227

B. Backward feed

Question 228

In evaporators, liquid entrainment is primarily due to foaming of the solution. Which of the following accessories is provided in the vapor line for removing the entrained liquid?
A. Bleed point
B. Vent
C. Catchall
D. Baffle

Answer 228

C. Catchall

Question 229

Oslo crystallizer : vaporization of solvent :: _____ : lowering of temperature
A. Surface-cooled crystallizer
B. Adiabatic evaporative cooler
C. Forced-circulation crystallizer
D. DTB crystallizer

Answer 229

A. Surface-cooled crystallizer

Question 230

2. Which of the following statements is FALSE?
   A. Swenson-Walker crystallizer is a batch crystallizer.
   B. Supersaturation is the driving potential for a crystal growth.
   C. The first stage of crystal formation is called nucleation.
   D. Crystal size in a continuous crystallizer depends on the rate of heat transfer, degree of turbulence, and degree of supersaturation.

Answer 230

A. Swenson-Walker crystallizer is a batch crystallizer.

Question 231

The overall process of crystallization from solution is considered to consist of the basic steps of nucleation (nucleus formation) and crystal growth. The driving force for the nucleation step as well as the growth step is:
A. temperature
B. concentration
C. supersaturation
D. crystal structure

Answer 231

C. supersaturation

Question 232

The heat of crystallization of Glauber’s salt is:
A. -243.3 kJ/kg
B. -75.6 kJ/kg
C. +149.3 kJ/kg
D. +8.4 kJ/kg

Answer 232

A. -243.3 kJ/kg

Question 233

Which of the following feels cold to the touch upon crystallization?
A. calcium nitrate tetrahydrate
B. potassium sulfate
C. plumbous chloride
D. zinc sulfate monohydrate

Answer 233

D. zinc sulfate monohydrate

Question 234

The McCabe ΔL law states that the:
A. molar heats of vaporization of components are nearly equal.
B. linear crystal growth rate depends on the degree of supersaturation.
C. linear crystal growth rate does not depend on the crystal size.
D. linear crystal growth rate depends on the crystal size.

Answer 234

C. linear crystal growth rate does not depend on the crystal size.

Question 235

The caking of crystals can be prevented by:
A. Maintaining high critical humidity
B. Maintaining low critical humidity
C. Coating the product with inert material
D. Both A and C

Answer 235

D. Both A and C

Question 236

The critical moisture content in case of drying indicates the ______ rate period.
A. Beginning of falling
B. Beginning of constant
C. End of falling
D. None of these

Answer 236

A. Beginning of falling

Question 237

Mechanism of moisture removal in case of freeze drying of food stuff is by:
A. Evaporation
B. Sublimation
C. Dehydration
D. Adsorption

Answer 237

B. Sublimation

Question 238

Batch tray dryers suffer from the disadvantage of:
A. High maintenance cost
B. Non-uniform and low production rate
C. High labor cost and low heat economy
D. All of the above

Answer 238

C. High labor cost and low heat economy

Question 239

For achieving rapid drying rate in a spray dryer, the diameter of the particles in the feed should be in the range of _____ microns (1 mm = 1000 microns).
A. 1-5
B. 10-60
C. 200-300
D. > 500

Answer 239

B. 10-60

Question 240

Which of the following is NOT a continuous dryer?
A. Drum dryer
B. Spray dryer
C. Tunnel dryer
D. Tray dryer

Answer 240

D. Tray dryer

Question 241

This is the moisture that can be removed by drying under the given percent relative humidity.
A. Equilibrium
B. Critical
C. Free
D. Bound

Answer 241

C. Free

Question 242

Rapid drying of solutions and suspensions in hot air or gas with dry particles or powders as product.
A. Tray
B. Supersonic
C. Spray
D. Splash

Answer 242

C. Spray

Question 243

During sensible heating of humid air,
A. relative humidity increases
B. dew point remains constant
C. dry and wet bulb temperature increase
D. both B and C

Answer 243

D. both B and C

Question 244

A psychrometer does not measure the _________ temperature of moist air.
A. dew point
B. dry bulb
C. wet bulb
D. none of these

Answer 244

A. dew point

Question 245

The minimum temperature up to which water can be theoretically cooled down in the cooling tower by evaporative cooling is equal to the __________ temperature of air.
A. wet bulb
B. dry bulb
C. saturation
D. dew point

Answer 245

A. wet bulb

Question 246

Which of the following properties remains constant during the adiabatic cooling of moist air?
A. wet bulb temperature
B. dry bulb temperature
C. relative humidity
D. specific humidity

Answer 246

A. wet bulb temperature

Question 247

Evaporative cooling process employs a combination of cooling and humidification in which:
A. sensible heat is added
B. sensible heat is removed and the latent heat is added
C. latent heat is removed
D. sensible heat is added and latent heat is removed

Answer 247

B. sensible heat is removed and the latent heat is added

Question 248

The analysis developed by Merkel for cooling towers is based upon which driving force?
A. density difference
B. specific volume difference
C. enthalpy potential difference
D. lower height

Answer 248

C. enthalpy potential difference

Question 249

The velocity at which individual particles from a fluidized bed are carried away by the fluid passing through it is defined as the:
A. minimum fluidization velocity
B. terminal velocity
C. elutriation velocity
D. superficial velocity

Answer 249

C. elutriation velocity

Question 250

All of the following are bed properties considered for fluidization EXCEPT:
A. bulk density
B. bed height
C. internal porosity
D. void fraction

Answer 250

C. internal porosity

Question 251

For a sphere falling in the constant drag coefficient regime, which of the following best describes the relationship of terminal velocity and diameter?
A. ut ∝ Dp
B. ut ∝ √Dp
C. ut ∝ Dp^2
D. ut ∝ 1/Dp

Answer 251

B. ut ∝ √Dp

Question 252

The terminal velocity of a small sphere settling in a viscous fluid varies as the:
A. first power of its diameter
B. inverse of the fluid viscosity
C. inverse square of the diameter
D. square of the difference in specific weights of solid and fluid

Answer 252

B. inverse of the fluid viscosity

Question 253

Drag force acting on a body does not depend upon the:
A. density of the fluid
B. density of the body
C. velocity of the body
D. projected area of the body

Answer 253

B. density of the body

Question 254

Minimum porosity for fluidization is:
A. that corresponding to static bed.
B. that corresponding to completely fluidized bed.
C. the porosity of the bed when true fluidization begins.
D. less than that of the static bed.

Answer 254

C. the porosity of the bed when true fluidization begins.

Question 255

Filter aids like asbestos, kieselguhr (diatomaceous earth) and purified wood cellulose are used to increase the porosity of the final filter cake and reduce cake resistance during filtration by deplugging. Filter aid is __________.
A. added to the feed slurry
B. precoated on the filter medium prior to filtration
C. separated from the cake by dissolving solids or by burning it off
D. all of the above

Answer 255

D. all of the above

Question 256

The flow of filtrate through the cake in plate and frame filter press follows a laminar flow. With this, which of the following will be valid?
A. Kozeny-Carman equation
B. Hagen-Poiseuille equation
C. Burke-Plummer equation
D. Fanning’s equation

Answer 256

A. Kozeny-Carman equation

Question 257

Which of the following best describes a compressible cake?
A. It has maximum porosity at the upstream side.
B. It has maximum porosity at the filter medium.
C. It has same porosity throughout the cake thickness.
D. Porosity gradient depends on the substance.

Answer 257

A. It has maximum porosity at the upstream side.

Question 258

The inlet pressure in a constant rate filtration _________.
A. increases continuously
B. decreases gradually
C. remains constant
D. none of these

Answer 258

A. increases continuously

Question 259

Which of the following represents the plot of filtrate volume versus time for constant pressure filtration?
A. Parabola
B. Straight line
C. Hyperbola
D. Exponential curve

Answer 259

A. Parabola

Question 260

Filtration rate through a filter cake is proportional to (where, S = filtering surface, R = specific cake resistance, μ = viscosity of the filtrate):
A. S
B. 1/R
C. 1/μ
D. all of the above

Answer 260

D. all of the above

Question 261

Which of the following is an advantage of using centrifugal force in place of gravitational force?
A. Far greater rates of separation
B. Possibility of achieving separations which are either not practically feasible, or actually impossible, in the gravitational field
C. Substantial reduction of the size of the equipment
D. All of the above.

Answer 261

D. All of the above.

Question 262

Moisture can be removed from lubricating oil using:
A. Tubular centrifuge
B. Clarifier
C. Sparkler filter
D. Vacuum leaf filter

Answer 262

A. Tubular centrifuge

Question 263

Ultracentrifuges running at speeds up to 100000 rpm is normally used for the:
A. separation of isotopes based on their density or molecular weights difference.
B. concentration of rubber latex.
C. separation of cream from milk.
D. dewaxing of lubricating oil.

Answer 263

A. separation of isotopes based on their density or molecular weights difference.

Question 264

If radius of a batch basket centrifuge is halved & the rpm is doubled, then the:
A. linear speed of the basket is doubled.
B. linear speed of the basket is halved.
C. centrifugal force is doubled.
D. capacity of centrifuge is increased.

Answer 264

C. centrifugal force is doubled.

Question 265

Which of the following statements is/are TRUE?
I. Maude and Whitmore equation is not applicable for uniformly sized particles.
II. Traces of solids are removed from the liquid in a clarifier.
A. I only
B. II only
C. I and II
D. None of these.

Answer 265

B. II only

Question 266

The state where settled solids and clear liquid are separated by a distinct single interface formed between.
A. Zone Settling
B. Dead Region
C. Free Settling
D. Critical Settling

Answer 266

D. Critical Settling

Question 267

It ensures that the settling solids do not adhere at the bottom of the sedimentation tank during operation.
A. Weir
B. Baffle
C. Paddle
D. Rake

Answer 267

D. Rake

Question 268

The opening of a 200-mesh screen (Taylor series) is
A. 0.0074 cm
B. 0.0074 mm
C. 0.0047 cm
D. 74 millimicrons

Answer 268

A. 0.0074 cm

Question 269

Which of the following is TRUE about dry and wet screening?
A. Wet screening requires addition of water to wash out fine materials.
B. Wet screening is limited to particles larger than 200 mesh.
C. Dry screening requires a downstream drying process.
D. Dry screening has higher efficiency due to lower probability of screen clogging.

Answer 269

A. Wet screening requires addition of water to wash out fine materials.

Question 270

A screening equipment that uses a high-speed rotating cylindrical perforated sheet for milling operations.
A. Oscillating Screens
B. Reels
C. Gyratory Screens
D. Trommels

Answer 270

B. Reels

Question 271

Which of the following is not a function of screen capacity?
A. Screening Surface
B. Atmospheric Humidity
C. Screen Opening Size
D. Screening Mechanism

Answer 271

B. Atmospheric Humidity

Question 272

In a size reduction crushing operation, the feed size is 10 to 50 mm while the product size is 2 to 10 mm. This is a case of ___________ crushing.
A. Fine
B. Ultrafine
C. Primary
D. Secondary

Answer 272

A. Fine

Question 273

___________ balls are capable of grinding the feed in a ball mill that gives the maximum efficiency.
A. Cast Iron
B. Minimum size
C. Elliptical
D. Maximum size

Answer 273

B. Minimum size

Question 274

Energy requirement (per unit mass of material crushed/ground) is highest for
A. Jaw crusher
B. Rod mill
C. Ball mill
D. Fluid energy mill

Answer 274

D. Fluid energy mill

Question 275

In liquid-liquid extraction, the number of phases at plait point is
A. 1
B. 2
C. 3
D. 4

Answer 275

A. 1

Question 276

When the solvent dissolves very little of solute, then
A. solvent of low latent heat of vaporization should be used
B. solvent of low freezing point should be used
C. large quantity of solvent is required to extract the solute
D. very small quantity of solvent is required

Answer 276

C. large quantity of solvent is required to extract the solute

Question 277

The commonly used solvent in supercritical extraction is
A. Methyl ketone
B. Water
C. Carbon tetrachloride
D. Carbon dioxide

Answer 277

D. Carbon dioxide

Question 278

Acetic acid will be most economically separated from a dilute solution of acetic acid in water by
A. Solvent extraction
B. Continuous distillation
C. Evaporation
D. Absorption

Answer 278

A. Solvent extraction

Question 279

The distribution coefficient of a solute A between solvents B and S is given by Y = 3.2X where Y = mass of A/mass of S in extract and X = mass of A/mass of B in raffinate. S and B are mutually immiscible. A solution containing 30% A in B is to be extracted in a single stage with recovery of 90%. How much S must be supplied per 100 kg of solution to attain the required condition?
A. 175.86 kg
B. 168.75 kg
C. 187.65 kg
D. 196.875 kg

Answer 279

D. 196.875 kg

Question 280

Liquid-liquid extraction is based on the difference in
A. solubility
B. partial pressure
C. viscosity
D. specific volume

Answer 280

A. solubility

Question 281

Which of the following sets of equipment is not used in liquid-liquid extraction?
A. Pachuka tank
B. Centrifugal extractors
C. Agitated vessels
D. Packed towers

Answer 281

A. Pachuka tank

Question 282

At equilibrium, the concentration of the liquid retained by the solid leaving any stage is ___ the concentration of the liquid overflow from the same stage.
A. higher than
B. the same as
C. lower than
D. has no relationship to

Answer 282

B. the same as

Question 283

The underflow in leaching is composed of the _________.
A. inert solid and the retained solution
B. the solvent and the dissolved solute
C. the solution which is not retained by the inert solid
D. the inert solid

Answer 283

A. inert solid and the retained solution

Question 284

The rate determining step in leaching is the _____________.
A. dissolution of solute in solvent
B. diffusion of solvent into the solid particles
C. diffusion of solute towards the surface of the solid
D. diffusion of the solute from the surface towards the bulk of the solvent

Answer 284

C. diffusion of solute towards the surface of the solid

Question 285

The overflow in leaching is composed of _____________.
A. inert solid and the retained solution
B. the solvent and the dissolved solute
C. the solution which is not retained by the inert solid
D. the inert solid

Answer 285

C. the solution which is not retained by the inert solid

Question 286

The N value for overflow is generally _____________.
A. <1
B. >1
C. equal to 1
D. equal to 0

Answer 286

D. equal to 0

Question 287

With an increase in temperature, the leaching rate increases due to
A. decreased liquid viscosity
B. increased diffusivity
C. both A and B
D. neither A nor B

Answer 287

C. both A and B

Question 288

Diameter to height ratio for a Raschig ring is
A. 1
B. 0.5
C. 2
D. 8

Answer 288

A. 1

Question 289

Flooding in a column results due to
A. High pressure drop
B. Low pressure drop
C. Low velocity of the liquid
D. High temperature

Answer 289

A. High pressure drop

Question 290

In packed column gas absorption, a transfer unit means that the
A. mole of solute is transferred in a unit height.
B. mass transfer coefficient will approach unity.
C. average driving force is equal to unity.
D. concentration range is equal to average driving force.

Answer 290

D. concentration range is equal to average driving force.

Question 291

At this point the entire column is filled with liquid and the gas now has to bubble through the liquid in the packing voids.
A. Flooding Point
B. Loading Point
C. Flooding Velocity
D. Mass Velocity

Answer 291

A. Flooding Point

Question 292

In a stripping or desorption operation, the equilibrium curve is
A. above the operating line
B. below the operating line
C. perpendicular with the tie line
D. linear

Answer 292

A. above the operating line

Question 293

As the gas velocity is increased the pressure drop also increased and some liquid started to be retained in the packings, this is known as
A. Flooding Point
B. Loading Point
C. Flooding Velocity
D. Mass Velocity

Answer 293

B. Loading Point

Question 294

In a gas absorption packed tower, the most economical gas velocity is considered to be _____ the flooding velocity.
A. equal to
B. about half
C. twice
D. greater than

Answer 294

B. about half

Question 295

In a gas absorption column, the pressure of the lean gas is expected to be _____ the pressure of the rich gas entering the column.
A. lower than
B. higher than
C. the same as
D. double

Answer 295

A. lower than

Question 296

Which tray type is the cheapest and has the lowest pressure drop?
A. Sieve Tray
B. Bubble-Cap Tray
C. Valve Tray
D. Packed Column

Answer 296

A. Sieve Tray

Question 297

Acetone is to be removed from air in an isothermal dilute absorber using pure water as solvent. The incoming air contains 5 mole% of acetone (yin = 0.05). The design equation to be used for obtaining the number of trays (N) of the absorber is, N+2 = 6 log (yin/yout). For 98% recovery of acetone, the number of trays required is/are:
A. 7
B. 8
C. 9
D. 10

Answer 297

C. 9

Question 298

A gas absorption tower needs to remove 99% of N2O4 in air. The packing will be 16-mm Pall rings. The gas enters at a rate of 1 lbm/s and contains 1.0 weight% N2O4 and 99% air at 300 K. The absorbent consists of water entering at 0.2 lbm/s. The N2O4 reacts readily with water. Assume Kya = 100 lbm N2O4/h-ft^3-atm-ΔY and the capacity of the column at the flood point is 1,000 lbm gas/h-ft^2. The units of y are lbm N2O4/lbm air. Suppose 75% of the flood point is use as operating gas mass velocity, find the diameter of the column.
A. 2.47 ft
B. 3.03 ft
C. 5.31 ft
D. none of these

Answer 298

A. 2.47 ft

Question 299

A gas absorption tower needs to remove 99% of N2O4 in air. The packing will be 16-mm Pall rings. The gas enters at a rate of 1 lbm/s and contains 1.0 weight% N2O4 and 99% air at 300 K. The absorbent consists of water entering at 0.2 lbm/s. The N2O4 reacts readily with water. Assume Kya = 100 lbm N2O4/h-ft^3-atm-ΔY and the capacity of the column at the flood point is 1,000 lbm gas/h-ft^2. The units of y are lbm N2O4/lbm air. Calculate the height of a theoretical stage (Hog) and the number of theoretical stages (Nog) assuming that all interface concentration is zero.
A. 5.4 ft, 6.69
B. 6.4 ft, 5.48
C. 7.4 ft, 4.61
D. none of these

Answer 299

C. 7.4 ft, 4.61

Question 300

A gas absorption tower needs to remove 99% of N2O4 in air. The packing will be 16-mm Pall rings. The gas enters at a rate of 1 lbm/s and contains 1.0 weight% N2O4 and 99% air at 300 K. The absorbent consists of water entering at 0.2 lbm/s. The N2O4 reacts readily with water. Assume Kya = 100 lbm N2O4/h-ft^3-atm-ΔY and the capacity of the column at the flood point is 1,000 lbm gas/h-ft^2. The units of y are lbm N2O4/lbm air. What is the height of the column?
A. 34.1 ft
B. 35.1 ft
C. 36.1 ft
D. none of these

Answer 300

A. 34.1 ft

Question 301

A gas absorption tower needs to remove 99% of N2O4 in air. The packing will be 16-mm Pall rings. The gas enters at a rate of 1 lbm/s and contains 1.0 weight% N2O4 and 99% air at 300 K. The absorbent consists of water entering at 0.2 lbm/s. The N2O4 reacts readily with water. Assume Kya = 100 lbm N2O4/h-ft^3-atm-ΔY and the capacity of the column at the flood point is 1,000 lbm gas/h-ft^2. The units of y are lbm N2O4/lbm air. The total weight of the Pall rings is ___ lbs.
A. 3204
B. 4204
C. 5204
D. none of these

Answer 301

C. 5204

Question 302

Weeping in a distillation column
A. increases tray efficiency
B. provides large interfacial surface for mass transfer
C. results due to very high gas velocity
D. results due to very low gas velocity

Answer 302

D. results due to very low gas velocity

Question 303

For a distillation column operating at minimum reflux, the
A. concentration of liquid and vapor leaving a plate will be same
B. reflux ratio will be maximum
C. number of plates required will be maximum
D. none of these

Answer 303

C. number of plates required will be maximum

Question 304

Rayleigh’s equation applies to _______ distillation.
A. Continuous
B. Steam
C. Differential
D. Flash

Answer 304

C. Differential

Question 305

In _______ distillation, a solvent is added to alter the relative volatility of the mixture to be separated.
A. Molecular
B. Azeotropic
C. Extractive
D. Flash

Answer 305

C. Extractive

Question 306

Fenske equation determines the
A. Maximum number of ideal plates
B. Height of the distillation column
C. Minimum number of theoretical plates
D. Optimum reflux ratio

Answer 306

C. Minimum number of theoretical plates

Question 307

For the same feed, feed quality and separation (in a distillation column), with the increase of total pressure, the number of ideal plates will
A. increase
B. decrease
C. remain same
D. data insufficient, can’t be predicted

Answer 307

A. increase

Question 308

The feed to fractionating column is changed from saturated vapor to saturated liquid. If the separation and reflux ratio remain unchanged, the number of ideal stages will
A. increase
B. decrease
C. remains same
D. depend on saturated boiling point; may increase or decrease

Answer 308

A. increase

Question 309

Which of the following is FALSE?
A. Constant pressure distillation cannot separate an azeotropic mixture.
B. Relative volatility of a binary mixture changes appreciably with the minor change in temperature.
C. The relative volatility of a binary mixture at azeotropic composition is unity.
D. Flash distillation is practiced on wide spread scale in petroleum refinery.

Answer 309

B. Relative volatility of a binary mixture changes appreciably with the minor change in temperature.

Question 310

In a binary distillation column, if the feed contains 40 mol% vapor, the q line will have a slope of
A. 1.5
B. -0.6
C. -1.5
D. 0.6

Answer 310

C. -1.5

Question 311

As the reflux ratio decreases, the
A. separation becomes more efficient
B. number of plates increases
C. column diameter increases
D. none of these

Answer 311

B. number of plates increases

Question 312

At what percentage (by volume) of alcohol composition, it forms an azeotrope with water?
A. 90
B. 91.5
C. 95
D. 99

Answer 312

C. 95

Question 313

The ideal size of round bubble caps to be used in industrial distillation column having a diameter of 3-6 meters is _______ cm.
A. 5
B. 15
C. 7.5
D. 50

Answer 313

B. 15

Question 314

A mixture containing 60 mol% benzene and 40 mol% toluene is fed to a distillation column at its dew point to be separated into a liquid distillate and a liquid bottoms product of 95 mol% and 5 mol% benzene, respectively. The distillation column is operated at a pressure where relative volatility is constant at a value of 2.48. The reflux ratio is 2. Determine the number of equilibrium stages.
A. 9
B. 11
C. 13
D. 15

Answer 314

D. 15

Question 315

If D represents the tank diameter, the approximate liquid depth in an agitation tank is equal to
A. 0.5 D
B. D
C. 0.75 D
D. 2 D

Answer 315

B. D

Question 316

The cost of handling of materials is considered under the _______ capital.
A. working
B. direct costs
C. fixed
D. indirect costs

Answer 316

A. working

Question 317

A certain pressure vessel manufacturer avoids doing reinforcements calculations for openings by always providing a reinforcing pad extending up to double the diameter of the opening and of the same material and thickness as that of the shell wall. If area compensation is accepted as a code guideline, his approach leads to safe design ____________________.
A. Only if the opening is on a spherical vessel
B. Only if the opening is on a vertical cylindrical vessel
C. Only if the opening is on a horizontal cylindrical vessel
D. Irrespective of the shape of the vessel

Answer 317

D. Irrespective of the shape of the vessel

Question 318

Poisson’s ratio of a material is the ratio of unit lateral strain to the unit axial elongation within its elastic limit. The value of Poisson’s ratio for structural and pressure vessel steel may be taken as _____.
A. 0.01
B. 0.3
C. 0.75
D. 0.95

Answer 318

B. 0.3

Question 319

The purest form of iron is __________.
A. Cast iron
B. Steel
C. Wrought iron
D. Pig iron

Answer 319

C. Wrought iron

Question 320

Wall thickness of Sch 40 pipes is _________ compared to that of Sch 80 pipes.
A. greater
B. less
C. the same
D. depends on the internal diameter

Answer 320

B. less

Question 321

Specific __________ is a dimensionless quantity.
A. Heat
B. Humidity
C. Weight
D. None of these

Answer 321

D. None of these

Question 322

With increase in temperature, the surface tension of water
A. increases
B. decreases
C. remains constant
D. increases linearly

Answer 322

B. decreases

Question 323

Surface tension is due to the __________ forces.
A. Viscous
B. Adhesive
C. Cohesive
D. All of these

Answer 323

C. Cohesive

Question 324

Fahrenheit and Centigrade scales have the same readings at __________.
A. -55°
B. -40°
C. -33°
D. -58°

Answer 324

B. -40°

Question 325

A batch reactor is most suitable for _______.
A. achieving cent percent conversion of reactants into products
B. large scale gaseous phase reactions
C. liquid phase reactions
D. obtaining uniform polymerization products in highly exothermic reactions

Answer 325

C. liquid phase reactions

Question 326

Pick out the wrong statement.
A. In a batch reactor, which is exclusively used for liquid phase reactions; temperature, pressure and composition may vary with time.
B. In a semi-batch reactor, one reactant is charged batchwise, while the other reactant is fed continuously.
C. In a continuous flow reactor, uniform concentration cannot be maintained throughout the vessel even in a well agitated system.
D. In a continuous flow reactor, both the reactants and the products flow out continuously.

Answer 326

C. In a continuous flow reactor, uniform concentration cannot be maintained throughout the vessel even in a well agitated system.

Question 327

Semi-batch reactor is preferred, when a/an _______.
A. highly exothermic reaction is to be controlled
B. undesirable side reaction (at high concentration of one of the reactants) is to be avoided
C. gas is to be reacted with liquid (e.g. hydrogenation of fat)
D. all of the above

Answer 327

D. all of the above

Question 328

In a semi-batch reactor, _______.
A. mixing takes place in axial direction only
B. velocity of reaction can be controlled
C. condition similar to plug flow reactor exists
D. residence time is constant

Answer 328

B. velocity of reaction can be controlled

Question 329

The range of a particular rotameter can be increased by _______.
A. using floats of different densities
B. no means
C. increasing the diameter of the float
D. decreasing the diameter of the float

Answer 329

A. using floats of different densities

Question 330

The velocity of sound in air is independent of changes in its _______.
A. humidity
B. pressure
C. temperature
D. none of these

Answer 330

B. pressure

Question 331

Which is an example of closed system?
A. Air compressor
B. Liquid cooling system of an automobile
C. Boiler
D. None of these

Answer 331

B. Liquid cooling system of an automobile

Question 332

No work is done by the system, when a reaction occurs at constant _______.
A. volume
B. temperature
C. pressure
D. none of these

Answer 332

A. volume

Question 333

The efficiency of a Carnot heat engine operating between absolute temperatures T1 and T2 (when T1 > T2) is given by (T1-T2)/T1. The coefficient of performance (C.O.P.) of a Carnot heat pump operating between T1 and T2 is given by:
A. T1/(T1-T2)
B. T2/(T1-T2)
C. T1/T2
D. T2/R1

Answer 333

A. T1/(T1-T2)

Question 334

In a P-V diagram (for an ideal gas), an isothermal curve will coincide within adiabatic curve (through a point), when:
A. Cp < Cv
B. Cp = Cv
C. Cp > Cv
D. Cp ≥ Cv

Answer 334

B. Cp = Cv

Question 335

With increase in compression ratio, the efficiency of the Otto engine
A. Increases
B. Decreases
C. Remains constant
D. Increases linearly

Answer 335

A. Increases

Question 336

A closed system is cooled reversibly from 100°C to 50°C. If no work is done on the system:
A. Its internal energy (U) decreases and its entropy (S) increases.
B. U and S both decrease.
C. U decreases but S is constant.
D. U is constant but S decreases.

Answer 336

B. U and S both decrease.

Question 337

If different processes are used to bring about the same chemical reaction, the enthalpy change is same for all of them. This is _________ law.
A. Hess’s
B. Kirchoff’s
C. Lavoisier and Laplace
D. None of these

Answer 337

A. Hess’s

Question 338

First law of thermodynamics deals with the _______.
A. direction of energy transfer
B. reversible processes only
C. irreversible processes only
D. none of these

Answer 338

A. direction of energy transfer

Question 339

The thermodynamic law, PVγ = constant, is not applicable in case of:
A. Ideal compression of air
B. Free expansion of an ideal gas
C. Adiabatic expansion of steam in a turbine
D. Adiabatic compression of a perfect gas

Answer 339

B. Free expansion of an ideal gas

Question 340

For an isothermal process, the internal energy of a gas _______.
A. increases
B. decreases
C. remains unchanged
D. data insufficient, can’t be predicted

Answer 340

C. remains unchanged

Question 341

There is a change in _______ during the phase transition.
A. volume
B. pressure
C. temperature
D. all of these

Answer 341

A. volume

Question 342

Fundamental principle of refrigeration is based on the ______ Law of thermodynamics.
A. Zeroth B. First C. Second D. Third

Answer 342

C. Second

Question 343

The expression for entropy change given by, ΔS = nR ln (V2/V1) + nCv ln (T2/T1) is valid for:
A. Reversible isothermal volume change
B. Heating of a substance
C. Cooling of a substance
D. Simultaneous heating and expansion of an ideal gas

Answer 343

D. Simultaneous heating and expansion of an ideal gas

Question 344

Which of the following is an undesirable characteristic of a refrigerant?
A. It should be non-explosive.
B. It should have a sub-atmospheric vapor pressure at the temperature in refrigerator coils.
C. Its vapor pressure at the condenser temperature should be very high.
D. None of these.

Answer 344

B. It should have a sub-atmospheric vapor pressure at the temperature in refrigerator coils.

Question 345

Pick out the correct statement.
A. Compression ratio of an Otto engine is comparatively higher than a diesel engine.
B. Efficiency of an Otto engine is higher than that of a diesel engine for the same compression ratio.
C. Otto engine efficiency decreases with the rise in compression ratio, due to decrease in work produced per quantity of heat.
D. Diesel engine normally operates at lower compression ratio than an Otto engine for an equal output of work.

Answer 345

B. Efficiency of an Otto engine is higher than that of a diesel engine for the same compression ratio.

Question 346

1/V(∂V/∂T)p is the mathematical expression for
A. Joule-Thomson co-efficient.
B. specific heat at constant pressure (Cp).
C. co-efficient of thermal expansion.
D. specific heat at constant volume (Cv).

Answer 346

C. co-efficient of thermal expansion.

Question 347

A liquid under pressure greater than its vapor pressure for the temperature involved is called a ____ liquid.
A. subcooled B. saturated C. non-solidifiable D. none of these

Answer 347

A. subcooled

Question 348

Lowering of condenser temperature (keeping the evaporator temperature constant) in case of vapor compression refrigeration system results in _______.
A. increased COP B. same COP C. decreased COP D. increased or decreased COP; depending upon the type of refrigerant

Answer 348

A. increased COP

Question 349

Requisites of a reversible process is that the _______.
A. system and surroundings pressure be equal
B. friction in the system should be absent
C. system and surroundings temperature be equal
D. none of these

Answer 349

B. friction in the system should be absent

Question 350

Pressure drop (Δp) for a fluid flowing in turbulent flow through a pipe is a function of velocity (V) as:
A. V^1.8 B. V^0.1 C. V^2.7 D. V^2

Answer 350

D. V^2

Question 351

With increase in molecular weight of the gas, the head developed by a centrifugal compressor will
A. decrease B. increase C. remain same D. be unpredictable

Answer 351

A. decrease

Question 352

Mach number is the ratio of the speed of the
A. fluid to that of the light
B. light to that of the fluid
C. fluid to that of the sound
D. sound to that of the fluid

Answer 352

C. fluid to that of the sound

Question 353

Which of the following valves will incur maximum pressure drop for the same discharge of water?
A. Globe valve
B. Gate valve
C. Needle valve
D. Butterfly valve

Answer 353

C. Needle valve

Question 354

Which of the following is most prone to pulsating discharge flow?
A. Centrifugal pump
B. Reciprocating pump
C. Gear pump
D. Axial flow pump

Answer 354

C. Gear pump

Question 355

Pascal’s law is valid, only when the fluid is _______.
A. frictionless and at rest
B. at rest
C. at rest and when the frictionless fluid is in motion
D. none of these

Answer 355

B. at rest

Question 356

Two piping system are said to be equivalent, when the __________ are same.
A. fluid flow rate & friction loss
B. length & friction factor
C. diameter & friction factor
D. length & diameter

Answer 356

A. fluid flow rate & friction loss

Question 357

In fluid flow, cavitation is caused, if the _____
A. fluid velocity decreases to zero
C. both A and B
B. total energy decreases
D. flow pressure approaches its vapor pressure at the prevailing temperature

Answer 357

D. flow pressure approaches its vapor pressure at the prevailing temperature

Question 358

Sewage sludge is _________ type of non-Newtonian fluid.
A. dilatant
C. pseudoplastic
B. Bingham plastic
D. None of these

Answer 358

B. Bingham plastic

Question 359

_________ pumps are axial flow pumps.
A. Turbine
B. Propeller
C. Diffuser
D. None of these

Answer 359

B. Propeller

Question 360

Viscosity of a liquid decreases _________ with rise in temperature.
A. exponentially
C. logarithmically
B. linearly
D. none of these

Answer 360

C. logarithmically

Question 361

The exit cone angle in case of a standard venturimeter is ________ the entrance cone angle.
A. smaller than
B. greater than
C. equal to
D. either A or B

Answer 361

A. smaller than

Question 362

A fluid is a substance, that _______.
A. has to be kept in a closed container
B. is almost incompressible
C. has zero shear stress
D. flows when even a small shear is applied to it

Answer 362

D. flows when even a small shear is applied to it

Question 363

The schedule number of a pipe is an indication of its:
A. size C. material density
B. roughness D. wall thickness

Answer 363

D. wall thickness

Question 364

Pump used for the transportation of molten sodium in a fast breader reactor is a/an _________ pump.
A. reciprocating C. electromagnetic
B. plunger D. gear

Answer 364

C. electromagnetic

Question 365

The most serious disadvantage of an orifice meter is:
A. It is not very accurate C. Most of the pressure drop is not recoverable
B. It is very costly D. It is not suitable for measuring gas flow

Answer 365

C. Most of the pressure drop is not recoverable

Question 366

Propeller type centrifugal pumps are most suitable for _______.
A. high capacity at high heads C. low capacity at high heads
B. high capacity at low heads D. low capacity at low heads

Answer 366

B. high capacity at low heads

Question 367

At high Reynolds number:
A. Inertial forces control and viscous forces are unimportant
B. Viscous forces predominate
C. Inertial forces are unimportant and viscous forces control
D. None of these

Answer 367

A. Inertial forces control and viscous forces are unimportant

Question 368

Viscosity of water is about __________ times that of air at room temperature.
A. 15 B. 55 C. 155 D. 1050

Answer 368

B. 55

Question 369

Cavitation can be prevented by:
A. Suitably designing the pump
B. Maintaining the suction head sufficiently greater than the vapor pressure
C. Maintaining suction head = developed head
D. Maintaining suction head lower than the vapor pressure

Answer 369

B. Maintaining the suction head sufficiently greater than the vapor pressure

Question 370

Which of the following exercises most powerful influence on the mechanical properties of steel?
A. Manganese B. Carbon C. Phosphorous D. Silicon

Answer 370

B. Carbon

Question 371

Bronze is an alloy of copper and _______.
A. lead B. tin C. nickel D. zinc

Answer 371

B. tin

Question 372

Cold worked steel parts are normally subjected to _______.
A. normalizing B. hardening C. annealing D. shot peening

Answer 372

C. annealing

Question 373

Mild steel is _______.
A. a low carbon steel (0.05 to 0.3% carbon)
B. highly resistant to corrosion (as much as stainless steel)
C. a high carbon steel (0.5 to 1.5% carbon)
D. very poor in strength & ductility

Answer 373

A. a low carbon steel (0.05 to 0.3% carbon)

Question 374

The softest material in Mho’s scale (for measuring hardness) is _______.
A. talc B. gypsum C. rubber D. none of these

Answer 374

A. talc

Question 375

he wall thickness of thin cylindrical shell with hemispherical ends is __________ that of the spherical ends.
A. equal to B. more than C. less than D. either (b) or (c); depends on maximum permissible internal pressure

Answer 375

B. more than

Question 376

A certain pressure vessel manufacturer avoids doing reinforcements calculations for openings by always providing a reinforcing pad extending up to double the diameter of the opening and of the same material and thickness as that of the shell wall. If area compensation is accepted as a code guideline, his approach leads to safe design ______.
A. only if the opening is on spherical vessel
B. only if the opening is on a vertical cylindrical vessel
C. only if the opening is on a horizontal cylindrical vessel
D. irrespective of the shape of the vessel

Answer 376

D. irrespective of the shape of the vessel

Question 377

The longitudinal stress induced in a thin-walled cylindrical vessel under internal pressure is
A. pd/2t B. pd/4t C. p/t D. pd/8t

Answer 377

B. pd/4t

Question 378

Joint efficiency (J) for a seamless pipe is _______.
A. 1 B. 0.85 C. 1.2 D. < 0.5

Answer 378

A. 1

Question 379

The wall thickness for a large high-pressure pipeline is determined by the consideration of the
A. axial tensile stress in the pip C. circumferential pipe wall tension
B. forces exerted by static and dynamic action at bends D. temperature stresses

Answer 379

C. circumferential pipe wall tension

Question 380

The ‘shanks system’ of leaching (i.e., counter-current multiple contact leaching) is used for _______.
A. recovery of tannins from the tree barks and woods
B. leaching sodium nitrate from Chilean nitrate bearing rock
C. both A & B
D. neither A nor B

Answer 380

C. both A & B

Question 381

The leaching solvent used in Baeyer’s process for the purification of bauxite is _______.
A. ammonium hydroxide C. sodium hydroxide
B. sodium carbonate D. ammonium carbonate

Answer 381

B. sodium carbonate

Question 382

Leaching of coarse solid lumps is also termed as _______.
A. decoction C. percolation
B. dissolution D. agitation and settling

Answer 382

C. percolation

Question 383

Degree of freedom for leaching and solvent extraction process is _______.
A. 1 B. 3 C. 0 D. 2

Answer 383

B. 3

Question 384

Leaching rate is independent of the _______.
A. agitation B. temperature C. particle size D. none of these

Answer 384

D. none of these

Question 385

The most important application of distribution law is in _______.
A. evaporation C. drying
B. liquid extraction D. distillation

Answer 385

B. liquid extraction

Question 386

Solvent used for extraction of oil is _______.
A. hexane C. furfurol
B. methyl ethyl ketone D. none of these

Answer 386

A. hexane

Question 387

In a liquid-liquid extraction, 10 kg of a solution containing 2 kg of solute C and 8 kg of solvent A is brought into contact with 10 kg of solvent B. Solvent A and B are completely immiscible in each other whereas solute C is soluble in both the solvents. The extraction process attains equilibrium. The equilibrium relationship between the two phases is Y* = 0.9X, where Y* is the kg of C/kg of B and X is kg of C/kg of A. Choose the correct answer.
A. The entire amount of C is transferred to solvent B.
B. Less than 2 kg but more than 1 kg of C is transferred to solvent B.
C. Less than 1 kg of C is transferred to B.
D. No amount of C is transferred to B.

Answer 387

A. The entire amount of C is transferred to solvent

Question 388

In case of constant underflow extraction operation, the _________ at all solute concentration.
A. Solids are drained to the same extent
B. Ratio of the insoluble to solution is constant
C. Both A & B
D. Neither A nor B

Answer 388

C. Both A & B

Question 389

Bollman extractor _______.
A. is a static bed leaching equipment C. is a centrifugal extractor
B. is used for extraction of oil from oilseed D. employs only counter-current extraction

Answer 389

B. is used for extraction of oil from oilseed

Question 390

Absorption factor, for a fixed degree of absorption from a fixed amount of gas should be:
A. 1 B. > 1 C. < 1 D. ≤ 1

Answer 390

B. > 1

Question 391

In a gas-liquid absorption column, for obtaining the maximum absorption efficiency:
A. liquid stream should be distributed uniformly.
B. gas stream should be distributed uniformly.
C. both gas as well as liquid streams should be distributed uniformly.
D. by passing should be completely avoided.

Answer 391

C. both gas as well as liquid streams should be distributed uniformly.

Question 392

The reciprocal of stripping factor is termed as _______.
A. selectivity index C. absorption factor
B. relative volatility D. Murphree efficiency

Answer 392

C. absorption factor

Question 393

In a packed absorption tower, if the equilibrium and operating lines are both straight lines, then the ratio, HETP/HTUog _________ the absorption factor.
A. increases with increase in C. both A and B
B. is one at unity value of D. neither A nor B

Answer 393

C. both A and B

Question 394

For the gas absorption, the height of a transfer unit, based on the gas phase is given by (G: superficial molar gas velocity, L: superficial molar liquid velocity, F: mass transfer co-efficient, mol/m²̇ a: interfacial area per unit volume of tower)
A. F/(FG.a) B. FG/(G.a) C. (G.a)/F.G D. L/(FG.G)

Answer 394

A. F/(FG.a)

Question 395

The operating velocity in the absorption tower is usually 40-50% of the flooding velocity. Packed absorption towers are normally designed for a pressure drop of about ______ mm of water column per meter height of packing.
A. 1-5 B. 20-40 C. 100-150 D. 1000-1500

Answer 395

B. 20-40

Question 396

In packed absorption tower, onset of flooding usually occurs at a pressure drop of about ________ mm of water column per meter height of packing.
A. 25-50 B. 50-75 C. 200-250 D. 750-1000

Answer 396

B. 50-75

Question 397

Pressure drop (Δp) and the superficial gas mass velocity (G) in case of packed absorption tower operating in the preloading range are related as
A. Δp = G B. Δp = G^0.5 C. Δp = G^2 D. Δp = 1/G^0.6

Answer 397

C. Δp = G^2

Question 398

Height equivalent to a theoretical plate (HETP) is the height of packing that will give the same separation as one theoretical plate in gas-liquid mass transfer operations like distillation, absorption/stripping and humidification/dehumidification. HETP which is experimentally determined, depends upon the _______.
A. flow rates of each fluid C. concentration of each fluid
B. type and size of packing D. all of these

Answer 398

D. all of these

Question 399

HETP is numerically equal to HTU, only when the operating line _______.
A. lies below the equilibrium line C. and equilibrium lines are parallel
B. lies above the equilibrium line D. is far from the equilibrium line

Answer 399

C. and equilibrium lines are parallel

Question 400

Pick out the wrong statement.
A. The slope of the stripping line is always less than unity.
B. For a given separation in a binary distillation column, with increase in reflux ratio (above the minimum reflux ratio), the fixed cost of the distillation column first increases and then decreases.
C. In Ponchon-Savart method of number of theoretical plate determination, the stripping and rectifying operating lines are vertical at total reflux.
D. Kremsor-Brown-Souder’s equation is used to calculate the efficiency of a plate tower.

Answer 400

C. In Ponchon-Savart method of number of theoretical plate determination, the stripping and rectifying operating lines are vertical at total reflux.

Question 401

Which of the following is not a valid assumption in continuous binary distillation for calculating the number of equilibrium stages by McCabe-Thiele’s method?
A. Sensible heat changes for vapor & liquid are negligibly small.
B. Reflux is not a saturated liquid.
C. Molar latent heats of the two components are equal.
D. Heat of mixing of normal liquid is assumed to be zero.

Answer 401

B. Reflux is not a saturated liquid.

Question 402

For ethanol-water system, the lowering of distillate quality from 95% to 92% will cause _______.
A. no change in theoretical plate requirement
B. marginal decrease in the number of
C. major decrease in the number of
D. none of these

Answer 402

B. marginal decrease in the number of

Question 403

Flooding in a distillation column is detected by a sharp _______.
A. increase in Murphree plate efficiency C. decrease in liquid hold up in the column
B. decrease in pressure drop D. increase in pressure drop

Answer 403

D. increase in pressure drop

Question 404

Polar organic compounds are normally used as separating agents for the azeotropic and extractive distillation. Which of the following is the most important factor to be considered for the choice of the separating agent for extractive distillation?
A. cost B. availability C. toxicity D. selectivity

Answer 404

D. selectivity

Question 405

The reflux to a distillation column is 100 moles/hour, when the overhead product rate is 50 moles/hr. The reflux ratio is _______.
A. 2 B. 0.5 C. 50 D. 150

Answer 405

A. 2

Question 406

Overall efficiency of the distillation column is _______.
A. The ratio of number of ideal plates to actual plates
B. The ratio of number of actual plates to ideal plates
C. Same as the Murphree efficiency
D. Always more than the point efficiency

Answer 406

A. The ratio of number of ideal plates to actual plates

Question 407

Inside the distillation columns, the _______.
A. highest temperature is near the feed plate
B. driving force for the liquid flow is its weight
C. vapors are not always at their dew points
D. all of the above

Answer 407

B. driving force for the liquid flow is its weight

Question 408

For a binary mixture with low relative volatility, _______.
A. use steam distillation
B. use molecular distillation
C. use high pressure distillation
D. an azeotrope may be formed during distillation

Answer 408

D. an azeotrope may be formed during distillation

Question 409

Vapor velocity in a distillation column for non-foaming mixture is in the range of _________ times the flooding velocity.
A. 0.1 to 0.3 B. 0.6 to 0.7 C. 0.85 to 0.95 D. 1.5 to 2

Answer 409

B. 0.6 to 0.7

Question 410

Which of the following is the most suitable for removing fine particles (< 1 micron diameter) from air below its dew point?
A. Venturi scrubber C. Cyclone separator
B. Electrostatic precipitator D. Fabric filter

Answer 410

B. Electrostatic precipitator

Question 411

Use of hydrated lime in water treatment
A. Before filtration, reduces the bacterial load on filters
B. After filtration, combats the corrosiveness of water due to the presence of O2 & CO2
C. Is to adjust the pH value
D. All of the above

Answer 411

D. All of the above

Question 412

Brackish water which contains mostly dissolved salt, can be purified by the _______ process.
A. Reverse osmosis C. Lime soda
B. Sand filter D. Permutit

Answer 412

A. Reverse osmosis

Question 413

Coagulant is used _________ filtration.
A. Before B. After C. During D. To avoid

Answer 413

A. Before

Question 414

Pick out the true statement pertaining to water treatment.
A. Slow sand filters can remove color completely
B. Activated carbon can be used for taste & odor control without subsequent filtration
C. Application of activated carbon reduces the temporary hardness of water
D. Normally, the turbidity is removed by adding a coagulant prior to sedimentation

Answer 414

D. Normally, the turbidity is removed by adding a coagulant prior to sedimentation

Question 415

Insufficient washing of sand grains in a rapid sand filter causes ______.
A. Air binding C. Mud balls
B. Shrinkage of filtering media D. Expansion of filtering media

Answer 415

C. Mud balls

Question 416

When larger particles e.g., grains are subjected to fluidization, the corresponding bed produced is termed as the _________ bed.
A. Spouted B. Sluggish C. Boiling D. Teeter

Answer 416

A. Spouted

Question 417

The uniformity of a gas fluidized bed depends upon the ______ of the solid particles.
A. Size C. Both A and B
B. Surface properties D. Neither A nor B

Answer 417

C. Both A and B

Question 418

Slugging occurs in a fluidized bed, if the bed is
A. Narrow B. Deep C. Both A & B D. Neither A nor B

Answer 418

C. Both A & B

Question 419

Operating principle of cyclone separator is based on the action of _________ dust particles.
A. Diffusion of C. Gravitational force on
B. Centrifugal force on D. Electrostatic force on

Answer 419

B. Centrifugal force on

Question 420

Forces acting on a particle settling in fluid are _________ forces.
A. Gravitational & buoyant C. Gravitational or centrifugal buoyant drag
B. Centrifugal & drag D. External, drag & viscous

Answer 420

C. Gravitational or centrifugal buoyant drag

Question 421

Which of the following is the most suitable for extraction in a system having very low-density difference?
A. Mixer-settler extractor C. Pulsed extractor
B. Centrifugal extractor D. Packed extraction tower

Answer 421

B. Centrifugal extractor

Question 422

Extraction of penicillin employs a ________ extraction column.
A. Centrifugal C. Plate
B. Packed D. None of these

Answer 422

A. Centrifugal

Question 423

_________ extractor uses centrifugal force for separating the two phases.
A. Treybal C. Podbielniäk
B. Schiebel D. None of these

Answer 423

C. Podbielniäk

Question 424

The ratio of the area of openings in one screen (Taylor series) to that of the openings in the next smaller screen is
A. 1.5 B. 1 C. √2 D. None of these

Answer 424

C. √2

Question 425

Increasing the capacity of a screen _______ the screen effectiveness.
A. Decreases C. Does not effect
B. Increases D. None of these

Answer 425

A. Decreases

Question 426

Screen capacity is expressed in terms of
A. Tons/hr B. Tons/ft² C. Both A & B D. Tons/hr-ft²

Answer 426

D. Tons/hr-ft²

Question 427

As particle size is reduced
A. Screening becomes progressively more difficult
B. Screening becomes progressively easier
C. Capacity and effectiveness of the screen is increased
D. None of these

Answer 427

A. Screening becomes progressively more difficult

Question 428

For sizing of fine materials, the most suitable equipment is a
A. Trommel C. Shaking screen
B. Grizzly D. Vibrating screen

Answer 428

D. Vibrating screen

Question 429

Which of the following will most accurately give the work required for size reduction of coal to -200 mesh in a ball mill?
A. Rittinger’s law B. Kick’s law C. Bond’s law D. None of these

Answer 429

A. Rittinger’s law

Question 430

Out of the following size reduction equipment, the maximum feed size can be accepted by the
A. Tube mill C. Jaw crusher
B. Ball mill D. Jet pulverizer

Answer 430

C. Jaw crusher

Question 431

During size reduction by a jaw crusher, the energy consumed decreases with the
A. Decreasing size of product at constant size of feed
B. Decreasing machine capacity
C. Increasing size of feed at constant reduction ratio
D. None of these

Answer 431

C. Increasing size of feed at constant reduction ratio

Question 432

Size reduction mechanism used in Jaw crushers is
A. Attrition B. Compression C. Cutting D. Impact

Answer 432

B. Compression

Question 433

Pick out the wrong statement.
A. Recycled coarse material to the grinder by a classifier is termed as circulating load
B. Wear and tear in wet crushing is more than that in dry crushing of materials
C. Size enlargement (opposite of size reduction) is not a mechanical operation
D. A ‘dust catcher’ is simply an enlargement in a pipeline which permits the solids to settle down due to reduction in velocity of the dust laden gas

Answer 433

C. Size enlargement (opposite of size reduction) is not a mechanical operation

Question 434

Traces of solids are removed from, liquid in a
A. Classifier C. Sparkler filter
B. Clarifier D. Rotary vacuum filter

Answer 434

B. Clarifier

Question 435

Which of the following is a batch sedimentation equipment?
A. Dust catcher C. Dry cyclone separator
B. Filter thickener D. Rotary sprayer scrubber

Answer 435

B. Filter thickener

Question 436

Separation of solid suspended in liquid into a supernatant clear liquid and a denser slurry employs a process termed as the
A. Coagulation B. Flocculation C. Sedimentation D. Clarification

Answer 436

C. Sedimentation

Question 437

Gravity settling process is not involved in the working of a
A. Hydrocyclone C. Dort-thickener
B. Classifier D. Sedimentation tank

Answer 437

A. Hydrocyclone

Question 438

A particle is settling in a liquid under Stokesian conditions. The free-falling velocity of the particle is proportional to
A. (particle diameter)^½ C. (particle diameter)²
B. particle diameter D. (particle diameter)³

Answer 438

B. particle diameter

Question 439

For the same heat transfer area and the terminal conditions, the ratio of the capacities of a single effect evaporator to a triple effect evaporator is
A. 3 B. 0.33 C. 1 D. 1.33

Answer 439

C. 1

Question 440

Evaporation of 1kg of water from a solution in a single effect evaporator requires about ______ kg of steam.
A. 0.4 - 0.6 B. 1-1.3 C. 1.8-2 D. 2 - 2.4

Answer 440

B. 1-1.3

Question 441

In a multiple effect evaporator, the effect of boiling point elevation is to
A. Reduce the capacity C. Increase the economy
B. Reduce the economy D. None of these

Answer 441

A. Reduce the capacity

Question 442

Which is the most suitable for the concentration of highly concentrated solution?
A. Open pan evaporation C. Agitated film evaporator
B. Long tube vertical evaporator D. None of these

Answer 442

A. Open pan evaporation

Question 443

In evaporators, lowering the feed temperature
A. Increases the heating area required C. Both A and B
B. Reduces the economy D. Decreases the heating area required

Answer 443

C. Both A and B

Question 444

n case of a vertical tube evaporator, with increase in the liquor level, the _________ is increased.
A. Velocity of circulation C. Both A and B
B. Liquor-film co-efficient D. Neither A and B

Answer 444

D. Neither A and B

Question 445

Crystal size in a continuous crystallizer depends upon the
A. Rate of heat transfer C. Degree of supersaturation
B. Degree of turbulence D. All of the above

Answer 445

D. All of the above

Question 446

The driving potential for the crystal growth during crystallization is the _________ of the solution.
A. Concentration C. Supersaturation
B. Viscosity D. Density

Answer 446

C. Supersaturation

Question 447

Duhring rule is important in solving problems on
A. Distillation B. Crystallization C. Evaporation D. Humidification

Answer 447

C. Evaporation

Question 448

Capacity of a rotary dryer depends on its
A. Rpm C. Both A & B
B. Inclination with ground surface D. Neither A nor B

Answer 448

C. Both A & B

Question 449

Drying of a solid involves _________ transfer.
A. Only heat C. Both heat and mass
B. Only mass D. None of these

Answer 449

C. Both heat and mass

Question 450

Advantage of continuous drying over batch drying is that the
A. Drying cost per unit weight of dried product is less
B. Product with more uniform moisture content is produced
C. Equipment size required is smaller
D. All of the above

Answer 450

D. All of the above

Question 451

Critical humidity of a solid salt means the humidity
A. Above which it will always become damp
B. Below which it will always stay dry
C. Both A and B
D. Above which it will always become dry and below which it will always stay damp

Answer 451

C. Both A and B

Question 452

If moisture content of solid on dry basis is X, then the same on wet basis is
A. X/(X + 1) B. X/(X - 1) C. (X + 1)/X D. (X - 1)/X

Answer 452

A. X/(X + 1)

Question 453

For continuous drying of granular or crystalline material, the dryer used is the _________ dryer.
A. Tunnel B. Tray C. Rotary D. None of these

Answer 453

C. Rotary

Question 454

The drying time between fixed moisture content within diffusion controlled ‘falling rate period’ is proportional to (assuming that drying occurs from all surfaces of the solid) (where, T = thickness of the solid)
A. √T
B. T
C. T^2
D. T^3

Answer 454

C. T^2

Question 455

Flights in a rotary dryer are provided to:
A. Lift and shower the solids thus exposing it thoroughly to the drying action of the gas
B. Reduce the residence time of solid
C. Increase the residence time of the solid
D. None of these

Answer 455

A. Lift and shower the solids thus exposing it thoroughly to the drying action of the gas

Question 456

A slurry is to be dried to produce flaky solid. Which dryer would you recommend?
A. Spray dryer
B. Drum dryer
C. Rotary dryer
D. Dielectric dryer

Answer 456

A. Spray dryer

Question 457

In the constant rate period of the rate of drying curve for batch drying,
A. Cracks develop on the surface of the solid
B. Rate of drying decreases abruptly
C. Surface evaporation of unbound moisture occurs
D. None of these

Answer 457

C. Surface evaporation of unbound moisture occurs

Question 458

Which of the following processes is followed by unsaturated air (with dry bulb temperature 12°C and relative humidity 47%) passing through water spray washer (temperature of water being constant at 40°C)?
A. Humidification only
B. Heating only
C. Both heating and humidification
D. Evaporative cooling

Answer 458

C. Both heating and humidification

Question 459

The temperature of water cooled in cooling tower is always ________ temperature of entering air.
A. More than the wet bulb
B. Less than the wet bulb
C. Equal to the wet bulb
D. Equal to the dry bulb

Answer 459

A. More than the wet bulb

Question 460

Humid volume, at a given temperature is a/an ________ function of humidity.
A. Inverse
B. Exponential
C. Linear
D. Logarithmic

Answer 460

C. Linear

Question 461

When the temperature and humidity of air is low, we usually use ________ draft cooling tower.
A. Natural
B. Forced
C. Induced
D. None of these

Answer 461

A. Natural

Question 462

At the boiling point of the liquid at the prevailing pressure, the saturated absolute humidity becomes
A. 1
B. 0
C. ∞
D. None of these

Answer 462

C. ∞

Question 463

n case of cooling towers, the ratio of the rates of heat and mass transfer is indicated by the ________ number.
A. Lewis
B. Grashoff
C. Sherwood
D. None of these

Answer 463

A. Lewis

Question 464

The humid volume may be increased by increasing the
A. Temperature at constant humidity
B. Humidity at constant temperature
C. Both A & B
D. Neither A nor B

Answer 464

C. Both A & B

Question 465

Relative humidity is the ratio of the
A. Partial pressure of the vapor to the vapor pressure of the liquid at room temperature
B. Partial pressure of the vapor to the vapor pressure of the liquid at gas temperature
C. Actual humidity to saturation humidity
D. None of these

Answer 465

B. Partial pressure of the vapor to the vapor pressure of the liquid at gas temperature

Question 466

The cooling effect in a cooling tower can be speeded up by
A. Increasing the air velocity and area of exposed wet surface
B. Reducing the barometric pressure
C. Reducing the humidity of the air
D. All of the above

Answer 466

D. All of the above

Question 467

The mass diffusivity, the thermal diffusivity and the eddy momentum diffusivity are same for Pr = Sc = _________
A. 1
B. 0.5
C. 10
D. 0

Answer 467

A. 1

Question 468

Dimension of mass diffusivity is the same as that of
A. Kinematic viscosity
B. Dynamic viscosity
C. Surface tension
D. Pressure

Answer 468

A. Kinematic viscosity

Question 469

For experimental determination of mass transfer co-efficient by wetted wall tower, the mass transfer area is
A. calculated
B. unknown
C. known
D. not required

Answer 469

C. known

Question 470

Pick out the wrong statement.
A. Mass transfer co-efficient does not account for gas-liquid diffusion.
B. Diffusion coefficient and mass transfer coefficient are not same in any mass transfer operation.
C. Contacting cold vapor-gas mixture with hot liquid exemplifies humidification process.
D. Contacting cold liquid with warm vapor-gas mixture exemplifies dehumidification process.

Answer 470

A. Mass transfer co-efficient does not account for gas-liquid diffusion.

Question 471

According to Chilton-Colburn analogy for mass transfer, (NaNSc)2/3 is equal to
A. f
B. f/2
C. 2f
D. 1/f

Answer 471

B. f/2

Question 472

Calculation of mass transfer co-efficient is mostly/normally done using _________ theory.
A. surface
B. film
C. penetration
D. none of these

Answer 472

B. film

Question 473

As per Gilliland’s equation, the diffusivity is
A. directly proportional to ‘T 1.5’.
B. inversely proportional to ‘P’.
C. dependent on the molecular volume & molecular weight of components.
D. All of these

Answer 473

D. All of these

Question 474

For turbulent mass transfer in pipes, the Sherwood number depends on the Reynolds number as
A. Re^0.33
B. Re^0.53
C. Re^0.83
D. Re

Answer 474

C. Re^0.83

Question 475

__________ equation applies to diffusivities in liquids.
A. Gilliland
B. Hirschfelder
C. Wilke and Chang
D. None of these

Answer 475

A. Gilliland

Question 476

Smoke is an example of
A. Solid dispersed in liquid
B. Solid dispersed in gas
C. Liquid dispersed in gas
D. Gas dispersed in liquid

Answer 476

B. Solid dispersed in gas

Question 477

Pick out the wrong statement.
A. The binary diffusivity in liquids is of the order of 10^-5 cm²/sec.
B. Molecular diffusion in solid is much faster than that in liquids.
C. Particles movement from higher concentration to lower concentration takes place in diffusion process.
D. According to Poiseuille’s law, the permeability decreases with increase in temperature for flow of a gas through a given capillary.

Answer 477

B. Molecular diffusion in solid is much faster than that in liquids.

Question 478

In physical terms, Schmidt number means
A. Thermal diffusivity / mass diffusivity
B. Thermal diffusivity /momentum diffusivity
C. Momentum diffusivity / mass diffusivity
D. Mass diffusivity / thermal diffusivity

Answer 478

C. Momentum diffusivity / mass diffusivity

Question 479

In case of liquids, the binary diffusivity is proportional to (where, T = temperature)
A. T
B. √T
C. T^2
D. 1/T

Answer 479

A. T

Question 480

Mass transfer coefficient is directly proportional to _________ theory.
A. Penetration
B. Surface renewal
C. Film
D. None of these

Answer 480

A. Penetration

Question 481

Diffusion in concentrated solutions differs from that of dilute solutions because of the change in the __________ with the concentration of the solution.
A. degree of ideality
B. viscosity
C. both A and B
D. neither B nor B

Answer 481

C. both A and B

Question 482

Thermal diffusivity is the most important in heat transfer by
A. conduction
B. radiation
C. condensation
D. natural convection

Answer 482

A. conduction

Question 483

Thermal conductivity of a gas at low density, _________ with increase in temperature.
A. decreases
B. increases
C. remains unchanged
D. may increase or decrease

Answer 483

B. increases

Question 484

If heat transfer rate varies with the time, it is termed as
A. Forced convection
B. Steady state conduction
C. Monochromatic radiation
D. None of these

Answer 484

D. None of these

Question 485

If the thermal conductivity of a wall material is independent _____ of temperature, the steady state temperature distribution in the very large thin plane wall having steady, uniform surface temperature follows ________ law.
A. Hyperbolic
B. Parabolic
C. Linear
D. Logarithmic

Answer 485

C. Linear

Question 486

When does the heat generated by fluid friction becomes appreciable compared to the heat transferred between the fluids?
A. At high fluid velocity
B. At low velocity
C. When fluid flows past a smooth surface
D. None of these

Answer 486

A. At high fluid velocity

Question 487

If h1 = inner film co-efficient and h2 = outer film co-efficient, then the overall heat transfer co-efficient is
A. always less than h1
B. always between h1 and h2
C. always higher than h2
D. dependent on metal resistance

Answer 487

B. always between h1 and h2

Question 488

Nusselt number is the ratio of the temperature gradient at the wall to _________.
A. Temperature difference
B. Heat flux
C. That across the entire pipe
D. None of these

Answer 488

C. That across the entire pipe

Question 489

In forced convection, the heat transfer depends on
A. Re, Pr
B. Re, Gr
C. Mainly Gr
D. Re only

Answer 489

A. Re, Pr

Question 490

Fouling factor for a heat exchanger is given by (where, U1 = heat transfer co-efficient of dirty surface U2 = heat transfer co-efficient of clean surface)
A. U1 - U2
B. 1/U1 - 1/U2
C. 1/U2 - 1/U1
D. U2 - U1

Answer 490

B. 1/U1 - 1/U2

Question 491

The Sieder-Tate correlation for heat transfer in turbulent flow in pipe gives Nu a Re^0.8, where, Nu is the Nusselt number and Re is the Reynolds number for the flow. Assuming that this relation is valid, the heat transfer co-efficient varies with the pipe diameter (D) as
A. D^-1.8
B. D^-0.2
C. D^0.2
D. D^1.8

Answer 491

B. D^-0.2

Question 492

Which of the following parameters of the fluid is not very important, while deciding its route in a shell and tube heat exchanger?
A. pressure
B. viscosity
C. corrosiveness & fouling characteristics
D. density

Answer 492

D. density

Question 493

In a shell and tube heat exchanger, the shell side fluid velocity can not be changed by changing the
A. tube layout
B. tube diameter
C. tube pitch
D. no. of baffle

Answer 493

B. tube diameter

Question 494

Stefen’s block body radiation law can also be derived from __________ law.
A. Kirchhoffs
B. Planck’s
C. Fourier’s
D. none of these

Answer 494

B. Planck’s

Question 495

Which of the following has the minimum absorptivity?
A. Aluminum foil
B. Coal dust
C. Refractory bricks
D. Iron plates

Answer 495

A. Aluminum foil

Question 496

Heat transfer by radiation mainly depends upon
A. its temperature
B. nature of the body
C. kind and extent of its surface
D. all of the above

Answer 496

D. all of the above

Question 497

All radiations in a black body are
A. reflected
B. refracted
C. transmitted
D. absorbed

Answer 497

D. absorbed

Question 498

At Pr > 1, conduction in an ordinary fluid flowing through a ________ heated pipe is limited to the
A. buffer zone
B. turbulent core
C. both (a) and (b)
D. viscous sub-layer

Answer 498

D. viscous sub-layer

Question 499

Pick out the correct statement.
A. 1 kcal/hr-m-°C is equal to 1 BTU/hr-ft-°F.
B. In steady state heat conduction, the only property of the substance which determines the temperature distribution, is the thermal conductivity.
C. In unsteady state heat conduction, heat flows in the direction of temperature rise.
D. In heat transfer by forced convection, Grashoff number is very important.

Answer 499

A. 1 kcal/hr-m-°C is equal to 1 BTU/hr-ft-°F.
B. In steady state heat conduction, the only property of the substance which determines the temperature distribution, is the thermal conductivity.

Question 500

In Biot number, the characteristic length used is the ratio of the ________ of the solid.
A. volume to surface area
B. perimeter to surface area
C. surface area to perimeter
D. surface area to volume

Answer 500

A. volume to surface area

Question 501

The radiation emitted by a black body is known as
A. Black radiation
B. Full radiation
C. Total radiation
D. All of these

Answer 501

D. All of these

Question 502

Which of the following is not used as a fuel in rocket propellant?
A. Liquid hydrogen
B. Liquid oxygen
C. Liquid hydrazine
D. Kerosene oil

Answer 502

B. Liquid oxygen

Question 503

Carburetor in a spark ignition engine is used to
A. Mix air-fuel in the desired ratio
B. Adjust the stroke length
C. Maintain a constant speed at varying loads
D. Increase the compression ratio

Answer 503

A. Mix air-fuel in the desired ratio

Question 504

Alcohols are not suitable as diesel engine fuel because the cetane number of alcohols is
A. Very low which prevents their ignition by compression
B. Very high which prevents their ignition by compression
C. Zero
D. None of these

Answer 504

A. Very low which prevents their ignition by compression

Question 505

Starting of a car takes time in winter, because the
A. Octane number of fuel is decreased
B. Fuel supply for ignition is not sufficient
C. Vaporisation of the fuel is decreased
D. Pour point of fuel decreases

Answer 505

C. Vaporisation of the fuel is decreased

Question 506

Volumetric composition of flue gas analyzed with the Orsat apparatus is: CO2 = 12%, O2 = 8%, CO = nil, N2 = 80%. This flue gas composition indicates that
A. Pure oxygen has been used for combustion
B. Nitrogen percentage in the fuel is very high
C. Excess air has been used for combustion
D. Hydrogen is not present in the fuel

Answer 506

C. Excess air has been used for combustion

Question 507

Presence of sulfur in the fuel fired in a furnace
A. Contributes to its heating value
B. Helps in electrostatic precipitation of ash from flue gases
C. Corrodes ducts & air preheater, if the flue gas temperature is low
D. All of the above

Answer 507

D. All of the above

Question 508

Large scale fire on fuel gas line is normally extinguished by
A. Water
B. Steam
C. Foam
D. Nitrogen

Answer 508

D. Nitrogen

Question 509

Which of the following accounts for maximum loss of energy in a coal fired boiler?
A. Incomplete combustion of fuel.
B. Outgoing flue gases.
C. Radiation heat losses.
D. Unburnt carbon in ash.

Answer 509

B. Outgoing flue gases.

Question 510

The difference between gross & net calorific values of fuel is due to the
A. sensible heat carried away by the flue gases.
B. heat carried away by the steam from the moisture content of the fuel.
C. heat lost by radiation.
D. heat carried away by steam from the combustion of hydrogen in the fuel.

Answer 510

D. heat carried away by steam from the combustion of hydrogen in the fuel.

Question 511

White smoke coming out of the chimney of a furnace indicates the use of
A. Low excess air
B. Very high excess air
C. Gaseous fuel in the furnace
D. Liquid fuel in the furnace

Answer 511

B. Very high excess air

Question 512

______________ explains the mechanism of catalysis.
A. Activated complex theory
B. Collision theory
C. Thermodynamics
D. None of these

Answer 512

A. Activated complex theory

Question 513

For every 10°C rise in temperature, the rate of chemical reaction doubles. When the temperature is increased from 30 to 70°C, the rate of reaction increases _______ times.
A. 8
B. 12
C. 16
D. 32

Answer 513

C. 16

Question 514

A first order reaction requires two equal sized CSTR. The conversion is
A. less when they are connected in series.
B. more when they are connected in series.
C. more when they are connected in parallel.
D. same whether they are connected in series or in parallel.

Answer 514

B. more when they are connected in series.

Question 515

Pick out the wrong statement pertaining to space velocity of flow reactors.
A. The unit of space velocity is (time)^-1.
B. The space velocity of 3 hr^-1 means that three reactor volumes of feed at specified conditions are being fed into the reactor every hour.
C. The space velocity of 3 hr^-1 means that one third reactor volume of feed at specified conditions are being fed into the reactor.
D. none of these.

Answer 515

C. The space velocity of 3 hr^-1 means that one third reactor volume of feed at specified conditions are being fed into the reactor.

Question 516

The rate constant of a chemical reaction decreases by decreasing the
A. pressure
B. concentration of reactants
C. temperature
D. duration of reaction

Answer 516

C. temperature

Question 517

. With decrease in temperature, the equilibrium conversion of a reversible endothermic reaction
A. decreases
B. increases
C. remains unaffected
D. increases linearly with temperature

Answer 517

A. decreases

Question 518

N’ plug flow reactors in series with a total volume ‘V’ gives the same conversion as a single plug flow reactor of volume ‘V’ for _________ order reactions.
A. first
B. second
C. third
D. any

Answer 518

D. any

Question 519

For a zero-order chemical reaction, the
A. half-life period is directly proportion to the initial concentration of the reactants.
B. plot of products concentration with time is a straight line through the origin.
C. products concentration increases linearly with time.
D. all (a), (b) and (c).

Answer 519

D. all (a), (b) and (c).

Question 520

Radioactive decay follows _________ order kinetics.
A. first
B. second
C. third
D. zero

Answer 520

A. first

Question 521

The dimensions of rate constant for reaction 3A → B are (L/gm mole)/min. Therefore, the reaction order is
A. 0
B. 1
C. 2
D. 3

Answer 521

C. 2

Question 522

In an incompressible flow of fluid, the fluid
A. Temperature remains constant
B. Compressibility is greater than zero
C. Density does not change with pressure & temperature
D. Is frictionless

Answer 522

C. Density does not change with pressure & temperature

Question 523

Which of the following pressure measuring device does not use an elastic element?
A. Bourdon
B. Bellow
C. Diaphragm
D. Piezoresistor

Answer 523

D. Piezoresistor

Question 524

Batch process is preferred over continuous process, when the
A. Product yields and quality cannot be achieved in continuous process, because of long residence time.
B. Sales demand of product is not steady.
C. Same equipment cannot be used for several processes of the same nature.
D. All of the above.

Answer 524

D. All of the above.

Question 525

In a/an __________ reactor, there is exchange of heat with the surroundings with sizeable temperature variation.
A. adiabatic
B. isothermal
C. non-adiabatic
D. none of these.

Answer 525

C. non-adiabatic

Question 526

A closed system is cooled reversibly from 100°C to 50°C. If no work is done on the system,
A. Its internal energy (U) decreases and its entropy (S) increases
B. U and S both decreases
C. U decreases but S is constant
D. U is constant but S decreases

Answer 526

B. U and S both decreases

Question 527

Heat of reaction at constant volume is identified with _________ change.
A. enthalpy
B. internal energy
C. either A or B
D. neither A nor B

Answer 527

B. internal energy

Question 528

Entropy of a substance remains constant during a/an __________ change.
A. Reversible isothermal
B. Irreversible isothermal
C. Reversible adiabatic
D. None of these

Answer 528

C. Reversible adiabatic

Question 529

Third law of thermodynamics is helpful in
A. prediction of the extent of a chemical reaction.
B. calculating absolute entropies of substances at different temperature.
C. evaluating entropy changes of chemical reaction.
D. both B and C

Answer 529

D. both B and C

Question 530

Heat is added at constant temperature in an ideal __________ cycle.
A. Stirling
B. Brayton
C. Rankine
D. None of these

Answer 530

A. Stirling

Question 531

The bank of tubes located at the back of the domestic refrigerators are the __________ tubes.
A. Refrigerant cooling
B. Evaporator
C. Condenser
D. Throttling

Answer 531

C. Condenser

Question 532

Which of the following is not a characteristic in choosing a refrigerant?
A. Vapor pressures
B. Flammability
C. Toxicity
D. Heat of fusion

Answer 532

D. Heat of fusion

Question 533

It contains saturated paraffin hydrocarbons, predominantly methane, together with other gases.
A. producer gas
B. synthesis gas
C. natural gas
D. pyrolysis gas

Answer 533

C. natural gas

Question 534

__________ the exhaust gas is an indication of the incomplete combustion of fuel.
A. Low temperature of
B. High temperature of
C. High % of CO in
D. High % of CO2 in

Answer 534

C. High % of CO in

Question 535

Gross and net calorific value of a fuel will be the same ___________.
A. if its ash content is zero.
B. If its carbon content is very low.
C. if its hydrogen/hydrogen compound content is zero.
D. under no circumstances.

Answer 535

C. if its hydrogen/hydrogen compound content is zero.

Question 536

A coal with high ash content
A. has higher calorific value.
B. is harder and stronger.
C. is not subjected to washing.
D. has low quantity of mineral matter.

Answer 536

B. is harder and stronger.

Question 537

Hydraulic radius of 6” x 12” cross section is __________ inches.
A. 2.5
B. 1.0
C. 2.0
D. 0.5

Answer 537

C. 2.0

Question 538

With increase in molecular weight of the gas, the head developed by a centrifugal compressor will
A. Decrease
B. Increase
C. Remain same
D. Unpredictable

Answer 538

A. Decrease

Question 539

For the transfer of solution of thick slurry, the pump used is a __________ pump.
A. Reciprocating
B. Gear
C. Diaphragm
D. Centrifugal

Answer 539

C. Diaphragm

Question 540

In case of supersonic flow of a fluid through pipeline, the ‘Mach number’ is
A. 0
B. 1
C. < 1
D. > 1

Answer 540

D. > 1

Question 541

The head loss in turbulent flow in a pipe varies
A. Directly as the velocity
B. Inversely as the square of the velocity
C. Approximately as the square of the velocity
D. Inversely as the square of the diameter

Answer 541

C. Approximately as the square of the velocity

Question 542

The __________ is measured by a piezometric opening.
A. Dynamic pressure
B. Static pressure
C. Total pressure
D. Point velocity

Answer 542

C. Total pressure

Question 543

The fluid velocity varies as the cube of the cylindrical pipe diameter in case of steady state laminar flow at constant pressure drop for __________ fluid.
A. Newtonian
B. Pseudoplastic
C. Dilatant
D. Bingham plastic

Answer 543

B. Pseudoplastic

Question 544

Momentum transfer in laminar flow of fluids results due to the
A. Viscosity
B. Density
C. Velocity gradient
D. None of these

Answer 544

C. Velocity gradient

Question 545

The dimension of kinematic viscosity is
A. ML^-T^-1
B. L^2T^-1
C. ML^-2T^-2
D. None of these

Answer 545

B. L^2T^-1

Question 546

Vertical storage vessels are never supported by __________ support.
A. bracket
B. saddle
C. skirt
D. lug

Answer 546

B. saddle

Question 547

__________ closure is the weakest enclosure for cylindrical vessels.
A. Hemispherical
B. Torisperical
C. Conical or flat plate
D. Elliptical

Answer 547

C. Conical or flat plate

Question 548

Safety valves are provided in chemical equipment to guard against excessive
A. temperature
B. pressure/pressure fluctuation
C. turbulence
D. noise

Answer 548

B. pressure/pressure fluctuation

Question 549

Scale up problem in design based on the similarity concept takes into account __________similarity.
A. geometrical
B. kinematic
C. dynamic
D. all of these

Answer 549

D. all of these

Question 550

For storing hazardous chemicals in large storage tanks, the minimum safe distance between the two tanks should range between __________ times the tank diameter.
A. 1 to 1.5
B. 2.5 to 3.5
C. 4 to 5
D. 6 to 8

Answer 550

A. 1 to 1.5

Question 551

When acetone is added in a two-layer mixture of methyl isobutyl ketone and water at 30°C, the acetone distributes between the two layers and the composition of the layer follows two solubility curves. For this system,
A. As the acetone concentration increases, the solubility curves approach each other.
B. Both the phases become identical at a particular common point on both solubility curves called plait point
C. The distribution curve which is a plot between x (acetone concentration in one phase) and y (acetone concentration in other phase) is analogous to x-y curve used in distillation and absorption terminates on the X-Y diagonal at the concentration of the plait point.
D. All of the above

Answer 551

D. All of the above

Question 552

A plait point is the point on the solubility curve, where the tie line reduces to a point. What is the number of plait point for a ternary system containing two pairs of partially miscible liquids?
A. 0
B. 1
C. 2
D. 3

Answer 552

A. 0

Question 553

With increase in temperature, the leaching rate increases because of the
A. Increased diffusivity
B. Decreased viscosity of liquid
C. Both A and B
D. Neither A nor B

Answer 553

C. Both A and B

Question 554

Leaching of sugar from sugar beets is done by
A. Hot water
B. Hexane
C. Dilute H2SO4
D. Lime water

Answer 554

A. Hot water

Question 555

The overall mass transfer co-efficient for the absorption of SO2 in air with dilute NaOH solution can be increased substantially by
A. Increasing the gas film coefficient
B. Increasing the liquid film coefficient
C. Increasing the total pressure
D. Decreasing the total pressure

Answer 555

A. Increasing the gas film coefficient

Question 556

In case of a desorber (stripper), the
A. Operating line always lies above the equilibrium curve
B. Operating line always lies below the equilibrium curve
C. Temperature remains unaffected
D. Temperature always increases

Answer 556

B. Operating line always lies below the equilibrium curve

Question 557

Bubble cap plate column is
A. A finite stage contactor
B. Used only for distillation, not for absorption
C. A differential stage contactor
D. A continuous contactor

Answer 557

A. A finite stage contactor

Question 558

Back-trapping in a distillation column results due to _________.
A. low gas velocity.
B. high gas velocity.
C. excessive liquid gradient over the tray.
D. low reflux ratio.

Answer 558

C. excessive liquid gradient over the tray.

Question 559

The reflux to a distillation column is 100 moles/hr, when the overhead product rate is 50 moles/hr. The reflux ratio is
A. 2
B. 0.5
C. 50
D. 150

Answer 559

A. 2

Question 560

If f = moles of vapor present per mole of feed, then the slope of feed line is (Mcabe-Thiele method)
A. (1 -f)/-f
B. -(f -1)/f
C. -1/f
D. -f/(1 - f)

Answer 560

A. (1 -f)/-f

Question 561

Slugging in a fluidized bed can be avoided by using
A. tall, narrow vessel
B. deep bed of solids
C. shallow beds of solids and proper choice of particle size
D. very large particles

Answer 561

C. shallow beds of solids and proper choice of particle size

Question 562

Fluidization has certain applications in the industry. For high conversion in a highly exothermic solid catalyzed reaction, it is best to use a
A. fixed bed reactor then a fluidized bed reactor
B. fluidized bed reactor then a fixed bed reactor
C. fixed bed reactor
D. fluidized bed reactor

Answer 562

B. fluidized bed reactor then a fixed bed reactor

Question 563

Filtration rate through a filter cake is proportional to (where, S = filtering surface, R = specific cake resistance, μ = viscosity of the filtrate)
A. S
B. 1/R
C. 1/μ
D. All of these

Answer 563

D. All of these

Question 564

Which of the following is the most suitable filter for separation of abrasive solids suspended in a corrosive liquid?
A. Tank filter (ex: Nutsch filter)
B. Filter press (ex: Plate and frame filter)
C. Vacuum filter (ex: Rotary disc filter)
D. Batch basket centrifuge

Answer 564

C. Vacuum filter (ex: Rotary disc filter)

Question 565

_______ centrifuge is the most suitable for separation of non-friable crystals.
A. Tubular bowl
B. Disc-bowl
C. Perforated horizontal basket continuous
D. Suspended batch basket

Answer 565

C. Perforated horizontal basket continuous

Question 566

For sizing of fine materials, the most suitable equipment is a
A. trommel
B. grizzly
C. shaking screen
D. vibrating screen

Answer 566

D. vibrating screen

Question 567

The sphericity of a cylinder of 1 mm diameter and length 3 mm is
A. 0.9
B. 0.78
C. 0.6
D. 0.5

Answer 567

A. 0.9

Question 568

In case of grinding in a ball mill
A. wet grinding achieves a finer product size than dry grinding.
B. its capacity decreases with increasing fineness of the products.
C. grinding cost and power requirement increases with increasing fineness of the products.
D. all of the above

Answer 568

D. all of the above

Question 569

The most commonly used substance to speed up the sedimentation of sewage is
A. lime
B. sulphuric acid
C. chlorine
D. sodium bisulphite

Answer 569

A. lime

Question 570

Dorr thickener is an equipment used for
A. Classification
B. Sedimentation
C. Clarification
D. Leaching

Answer 570

B. Sedimentation

Question 571

The relation, Sc = Pr = 1, is valid, when the mechanism of __________ transfer is same.
A. Mass and momentum
B. Momentum and heat
C. Heat and mass
D. Heat, mass and momentum

Answer 571

C. Heat and mass

Question 572

According to this theory, the mass transfer coefficient is directly proportional to diffusivity.
A. Penetration theory
B. Chilton theory
C. Film theory
D. Colburn theory

Answer 572

C. Film theory

Question 573

Diffusivity in concentrated solution differs from that in dilute solutions, because of changes in
A. Viscosity with concentration
B. Degree of ideality of the solution
C. Both A and B
D. Neither A nor B

Answer 573

C. Both A and B

Question 574

What is the diffusivity of oxygen in air at 25°C and 1 atm?
A. 0.175 cm^2/s
B. 0.202 cm^2/s
C. 0.156 cm^2/s
D. 0.207 cm^2/s

Answer 574

D. 0.207 cm^2/s

Question 575

The dimension of diffusivity is the same as that of the
A. density
B. molar concentration
C. kinematic viscosity
D. pressure drop

Answer 575

C. kinematic viscosity

Question 576

Which of the following is false?
A. The binary diffusivity in liquids is of the order of 10^-6 cm^2/s.
B. Molecular diffusion in solid is much faster than that in liquids.
C. In diffusion, particle movement takes place from higher concentration to lower concentration.
D. None of the above.

Answer 576

B. Molecular diffusion in solid is much faster than that in liquids.

Question 577

The ratio of momentum diffusivity to mass diffusivity is the ________ number.
A. Prandtl
B. Nusselt
C. Sherwood
D. Schmidt

Answer 577

D. Schmidt

Question 578

The emissivity of a polished silver body is __________, as compared to black body.
A. same
B. low
C. very low
D. high

Answer 578

C. very low

Question 579

Wavelength corresponding to the maximum energy is inversely proportional to the absolute temperature. This is __________ law.
A. Stefan’s
B. Dalton’s
C. Wein’s
D. Kirchhoff’s

Answer 579

C. Wein’s

Question 580

Which is the best tube arrangement (in a shell and tube heat exchanger) if the fluids are clean and non-fouling?
A. Square pitch
B. Triangular pitch
C. Diagonal square pitch
D. None of these.

Answer 580

B. Triangular pitch

Question 581

Baffles provided on the shell side of a shell and tube heat exchanger are meant for
A. Providing support for the tubes
B. Improving heat transfer
C. Both A & B
D. Preventing the fouling of tubes & stagnation of shell side fluid

Answer 581

C. Both A & B

Question 582

Heat Transfer by conduction in the turbulent core of a fluid flowing through a heated pipe is negligible, if the value of Prandtl number is
A. 0.2
B. 0.4
C. 0.6
D. 0.8

Answer 582

C. 0.6

Question 583

Film coefficients are semiempirical in nature. Which of the following affects film coefficients?
A. Physical properties of the fluid
B. Type and velocity of the flow
C. Geometry of the physical system
D. All of the above.

Answer 583

D. All of the above.

Question 584

The overall resistance for heat transfer through a series of flat resistances, is the _____ of the resistances.
A. Arithmetic mean
B. Geometric mean
C. Product
D. Sum

Answer 584

D. Sum

Question 585

A fluid is flowing inside the inner tube of a double pipe heat exchanger with diameter D. For a fixed mass flow rate, the tube side heat transfer coefficient for turbulent flow conditions is proportional to
A. D^0.8
B. D^0.2
C. D^-1
D. D^-1.8

Answer 585

B. D^0.2

Question 586

Minimum recommended baffle spacing in a shell and tube heat exchanger is about _____ of the shell diameter.
A. 20%
B. 50%
C. 66%
D. 80%

Answer 586

A. 20%

Question 587

If heat transfer rate varies with time, the process is called
A. Forced convection
B. Unsteady state heat transfer
C. Monochromatic radiation
D. Lumped capacity system

Answer 587

B. Unsteady state heat transfer

Question 588

Vibrations in the tubes of a shell and tube heat exchanger are due to the
A. Flow of fluid in the tube and shell sides
B. Oscillations in the flow of shell/tube side fluids
C. Vibrations transmitted through piping and/or supports due to external reasons
D. All of the above.

Answer 588

D. All of the above.

Question 589

Which of the following forced convection heat transfer equation accounts for the liquid viscosity effect for viscous liquids?
A. Dittus-Boelter equation
B. Sieder-Tate equation
C. Chilton equation
D. Stokes equation

Answer 589

B. Sieder-Tate equation

Question 590

Which of the following is generally considered as opaque surface towards radiation?
A. gases
B. liquids
C. solids
D. both B and C

Answer 590

D. both B and C

Question 591

What is the specific humidity, if pressure of water is 5 atm and total pressure is 10 atm?
A. 25%
B. 50%
C. 75%
D. 100%

Answer 591

D. 100%

Question 592

It results from mixing warm, highly saturated tower discharge air with cooler ambient air that lacks the capacity to absorb all the moisture as vapor.
A. Drifting
B. Fogging
C. Blowdown
D. Recirculation

Answer 592

B. Fogging

Question 593

What is the difference in the density of dry air at 1 atm and 25°C and moist air with 50% relative humidity under the same conditions? (kg/m^3)
A. 1.987
B. 1.178
C. 0.648
D. 0.007

Answer 593

D. 0.007

Question 594

Drying of refractory is normally carried out in a __________ dryer.
A. Open pan
B. Tray
C. Rotary vacuum
D. Truck/tunnel

Answer 594

D. Truck/tunnel

Question 595

Evaporation of 1kg of water from a solution in a single effect evaporator requires about ______ kg of steam.
A. 0.4 - 0.6
B. 1-1.3
C. 1.8-2
D. 2 - 2.4

Answer 595

B. 1-1.3

Question 596

It occurs when solutions deposit solid materials on heating surfaces as result of decomposition or decrease in solubility causing reduction in overall heat transfer coefficient.
A. Frothing
B. Scaling
C. Crystallization
D. Nucleation

Answer 596

B. Scaling

Question 597

In most of the vacuum crystallizer, vacuum is generally produced by means of a
A. Suction pump
B. Compressed air jet
C. Steam jet ejector with a barometric condenser
D. None of these

Answer 597

C. Steam jet ejector with a barometric condenser

Question 598

In the reaction CaO(s) + 2HCl(g) → CaCl2(aq) + H2O(l), which of the following can be used to measure the reaction rate?
A. change in pressure per time
B. change in total mass per time
C. change in pH per time
D. change in volume per time

Answer 598

C. change in pH per time

Question 599

The reactions with low activation energy are
A. always spontaneous
B. slow
C. fast
D. non-spontaneous

Answer 599

C. fast

Question 600

The reaction rate of a certain reaction is first order with respect to reactant X and second order with respect to reactant Y. Which of the following is a unit of the reaction constant?
A. L^2/mol^2·min
B. M/s
C. L/mol^2·min
D. 1/M·s

Answer 600

A. L^2/mol^2·min

Question 601

Half-life period of a chemical reaction is proportional to Cao^1, if the reaction is of _____ order.
A. First
B. Zero
C. Second
D. Third

Answer 601

C. Second

Question 602

In a continuous flow stirred tank reactor, the composition of the exit stream
A. Is same as that in the reactor
B. Is different than that in the reactor
C. Depends upon the flow rate of inlet stream
D. None of these

Answer 602

A. Is same as that in the reactor

Question 603

. A high space velocity means that a given
A. Reaction can be accomplished with small reactor
B. Conversion can be obtained with a high feed rate
C. Both A and B
D. None of these

Answer 603

C. Both A and B

Question 604

For identical flow rate and feed composition, X plug flow reactors (PFR) in series with a total volume V gives the same conversion as single
A. CSTR of volume V
B. PFR of volume V
C. CSTR of volume V/X
D. PFR of volume V/X

Answer 604

B. PFR of volume V

Question 605

In a/an __________ reactor, there is exchange of heat with the surroundings with sizeable temperature variation.
A. Adiabatic
B. Isothermal
C. Non-adiabatic
D. None of these

Answer 605

C. Non-adiabatic