Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

DAY 2 > Mass Transfer > Flashcards

Mass Transfer Flashcards

1
Q

Which of the following is the most suitable for extraction in a system having very low density difference ?

Centrifugal extractor

A

Centrifugal extractor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

When the temperature and humidity of air is low, we usually use __________ draft cooling tower.

natural

A

natural

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

__________ columns are used for liquid dispersion in a continuous gas phase.

Packed

A

Packed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which is the controlling factor for a drum drier?

Heat transfer

A

Heat transfer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

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

higher relative humidity

A

higher relative humidity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

In batch distillation with constant reflux, overhead product composition __________ with time.

decreases

A

decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

To increase the absorption factor, (where, G = gas flow rate, S = solvent flow rate)

increase ‘S’ and decrease ‘G’.

A

increase ‘S’ and decrease ‘G’.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

In case of an absorber, the operating

line always lies above the equilibrium curve.

A

line always lies above the equilibrium curve.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Absorption accompanied with chemical reaction is exemplified by the absorption of

SO2 in alkaline solution.

A

SO2 in alkaline solution.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Which of the following liquid-vapor contacting devices provides maximum contact surface area for a particular duty ?

Wetted wall column

A

Wetted wall column

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

The equipment frequently used for adiabatic humidification-cooling operation with recirculating liquid is

spray chamber

A

spray chamber

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The operation involved when the soluble material is largely on the surface of an insoluble solid and is merely washed off by the solvent is called

elutriation or elution

A

elutriation or elution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

In the constant rate period of the rate of drying curve for batch drying,

surface evaporation of unbound moisture occurs.

A

surface evaporation of unbound moisture occurs.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

It takes 6 hours to dry a wet solid from 50% moisture content to the critical moisture content of 15%. How much longer it will take to dry the solid to 10% moisture content, under the same drying conditions? (The equilibrium moisture content of the solid is 5%).

A

71 min

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

The reason for preferring packed towers over plate towers in distillation practice is that the packed tower operation gives

A

low pressure drop and low hold up.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Compound A is extracted from a solution of A + B into a pure solvent S. A Co-current unit is used for the liquid-liquid extraction. The inlet rate of the solution containing A is 200 moles of B/hr.m2 and the solvent flow, rate is 400 moles of S/m2. hr. The equilibrium data is represented by Y = 3X2 , where Y is in moles of a A/moles of B and X is in moles A/moles of S. The maximum percentage extraction achieved in the unit is

50%

A

50%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Wetted wall tower experiment determines the

mass transfer co-efficient.

A

mass transfer co-efficient.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

With decrease in the throughput (compared with the design capacity) for a bubble cap distillation column, its efficiency

increases

A

increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

The equilibrium liquid composition compared to the vapor composition in case of azeotropic mixture is

same

A

same

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Out of the following gas-liquid contacting devices, for a given set of operating conditions, gas pressure drop is the least in __________ tower.

wetted wall

A

wetted wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Free flowing granular materials can be best dried in a __________ drier.

rotary

A

rotary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

In case of an ideal solution, the total vapor pressure varies __________ with the composition expressed as mole fraction,

linearly

A

linearly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

If the specific heats of a gas and a vapor are 0.2KJ/Kg.°K and 1.5 KJ/Kg.°K respectively, and the humidity is 0.01; the humid heat in KJ/°Kg. is

0.215

A

0.215

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

At the same gas flow rate, the pressure drop in a packed tower being irrigated with liquid __________ that in dry packed tower.

is greater than

A

is greater than

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

The partial pressure distribution of an ideal gas diffusing through another stagnant ideal gas at steady state follows a/an __________ law.

exponential

A

exponential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

(NRe . NSc) is termed in mass transfer operation as the __________ number.

Peclet

A

Peclet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

__________ column is the most suitable for achieving the best performance for mass transfer operations involving liquid with dispersed solids.

Plate

A

Plate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

When the feed to a distillation column is a saturated liquid, slope of the feed line is

infinity

A

infinity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

If the solubilities of different components (in a liquid-liquid extraction system) increase with rise in temperature, then the temperature above which they dissolve completely is known as the critical solution temperature (CST or consolute temperature). If solubilities increase with decrease in temperature, then CST is the temperature below which they dissolve completely. If a binary system has no critical solution temperature, it implies that

on heating, a vapor phase will appear ; while on cooling, a solid phase will appear.

A

on heating, a vapor phase will appear ; while on cooling, a solid phase will appear.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

At equilibrium the concentration of water in vapour phase (C)in kg/m3 of air space and the amount of water (m) adsorbed per kg of dry silica gel are related by, C = 0.0667m. To maintain dry conditions in a room of air space 100m3 containing 2.2 kg of water vapour initially, 10 kg of dry silica gel is kept in the room. The fraction of initial water remaining in the air space after a long time (during which the temperature is maintained constant) is

0.4

A

0.4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Percentage saturation is __________ the relative saturation.

always smaller than

A

always smaller than

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Under conditions of flooding in packed tower, the gas pressure drop

is maximum

A

is maximum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

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).

10-60

A

10-60

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Weight of 1 m3 of humid air as compared to 1 m3 of dry air, under the same conditions, is

less

A

less

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

In a counter-current liquid extractor

only one of the liquids may be pumped at any desired rate.

A

only one of the liquids may be pumped at any desired rate.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Prandtl number for water at 20°C is about

7

A

7

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Steam distillation is used to

avoid thermal decomposition of a component.

A

avoid thermal decomposition of a component.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

A slurry is to be dried to produce flaky solid. Which dryer would you recommend ?

Spray dryer

A

Spray dryer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Large scale drying of wheat is done in a __________ dryer.

spouted bed

A

spouted bed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Azeotropic distillation is employed to separate

constant boiling mixture.

A

constant boiling mixture.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

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 )

T^2

A

T^2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

At the boiling point of the liquid at the prevailing pressure, the saturated absolute humidity becomes

∞

A

∞

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Dorr thickener is an equipment used for

sedimentation

A

sedimentation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

A 25 cm x 25 cm x 1 cm flat sheet weighing 1.2 kg initially was dried from both sides under constant drying rate conditions. It took 1500 seconds for the weight of the sheet to reduce to 1.05 kg. Another 1m x 1m x 1cm flat sheet of the same material is to be dried from one side only.Under the same constant drying rate conditions, the time required for drying (in seconds) from its initial weight of 19.2 kg to 17.6 kg is

1000

A

1000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

In an absorption coloumn, the flooding velocity for random packing is __________ that for stacked/regular packing.

smaller than

A

smaller than

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

In a binary distillation column, if the feed contains 40 mole % vapour, the q line will have a slope of

-1.5

A

-1.5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Radioactive nuclear waste is treated in

pulsed column extractor

A

pulsed column extractor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Heat sensitive materials like certain pharmaceuticals and food stuffs can be dried in a/an __________ dryer.

freeze

A

freeze

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Molecular seives are regenerated by heating to __________ °C.

200-330

A

200-330

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Large scale drying of sugar is done in a __________ dryer.

rotary

A

rotary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

The drying time between fixed moisture contents within the ‘constant rate period’ is proportional to (assuming that drying occurs from all surfaces of the solid) (where, T = thickness of the solid )

T

A

T

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Large quantity of silica gel is normally dried in a __________ dryer.

through circulation

A

through circulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Hydrogenation of oil is carried out in a/an __________ in Vanaspati manufacturing plant.

agitated vessel

A

agitated vessel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Which of the following equipments is not used for gas dispersion ?

Spray towers

A

Spray towers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

Which of these columns incurs the lowest pressure drop ?

Packed column (with stacked packing)

A

Packed column (with stacked packing)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

Which of the following same diameter columns gives lowest pressure drop per unit height ?

Packed column (stacked)

A

Packed column (stacked)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Operating velocity in a packed tower is usually __________ the flooding velocity.

half

A

half

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

The percentage humidity is less than the relative humidity only at __________ percent humidity.

both zero and hundred

A

both zero and hundred

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Minimum possible diameter of a packed coloumn is decided mainly by the

flooding

A

flooding

59
Q

Flooding in a vapor-liquid contacting equipment occurs in a tray, when the pressure drop through a tray is __________ the liquid head available in the downcomer.

more than

A

more than

60
Q

Milk is dried usually in a __________ dryer.

spray

A

spray

61
Q

At a given equilibrium pressure, with increase in temperature, the concentration of adsorbed gas on solid adsorbant

decreases

A

decreases

62
Q

Which of the following equipments is not used for liquid dispersion ?

Agitated vessels

A

Agitated vessels

63
Q

Diameter of raschig rings used in packed tower in industry is normally around __________ inches.

2

A

2

64
Q

In physical terms, Schmidt number means

momentum diffusivity/mass diffusivity.

A

momentum diffusivity/mass diffusivity.

65
Q

In case of liquids, the binary diffusivity is proportional to (where, T = temperature)

T

A

T

66
Q

Mass transfer co-efficient is directly proportional to DAB0.5, according to __________ theory.

penetration

A

penetration

67
Q

Diameter to height ratio for a rashig ring is

1

A

1

68
Q

In liquid-liquid extraction, the number of phases at plait point is

1

A

1

69
Q

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.

The entire amount of C is transferred to solvent B.

A

The entire amount of C is transferred to solvent B.

70
Q

If Rm is the minimum reflux ratio, the optimum reflux ratio may be around __________ Rm.

1.2 to 1.5

A

1.2 to 1.5

71
Q

Mass transfer co-efficient varies as DAB0.5, according to the __________ theory.

surface renewal

A

surface renewal

72
Q

Unsaturated air (with dry bulb and wet bulb temperatures being 45°C and 25°C respectively) is passed through a water spray chamber maintained at 23°C. The air will be cooled and

humidified with wet bulb temperature decreasing.

A

humidified with wet bulb temperature decreasing.

73
Q

The individual mass transfer co-efficients (moles/m2 . s) for absorption of a solute from a gas mixture into a liquid solvent are, KL = 4.5 and KG = 1.5. The slope of the equilibrium line is 3. Which of the following resistance (s) is (are) controlling ?

gas side

A

gas side

74
Q

According to the Fenske equation, what will be the minimum number of plates required in a distillation column to separate an equimolar binary mixture of components A and B into an overhead fraction containing 99 mol% A and a bottom fraction containing 98 mol% B ? Assume that relative volatility (αAB = 2) does not change appreciably in the coloumn.

12

A

12

75
Q

The relative volatility of a binary mixture at the azeotropic composition is

1

A

1

76
Q

Relative volatility varies with the concentration of component for an ideal solution. The relative volatity of a binary mixture may be defined as the ratio of vapor pressure of component ‘A’ to that of component ‘B’, when

Vapor phase obeys Dalton’s law and liquid phase obeys Raoult’s law.

A

Vapor phase obeys Dalton’s law and liquid phase obeys Raoult’s law.

77
Q

Bound moisture is that liquid which exerts an equilibrium vapor pressure __________ that of the pure liquid at the given temperature.

less than

A

less than

78
Q

Lewis number (Le) is

Sc / Pr

A

Sc / Pr

79
Q

Moisture content of a substance when at equilibrium with a given partial pressure of the vapour is called the __________ moisture.

equilibrium

A

equilibrium

80
Q

All moisture in a non-hygroscopic material is the __________ moisture.

unbound

A

unbound

81
Q

Separation of __________ employs gaseous diffusion process.

isotopes of uranium

A

isotopes of uranium

82
Q

The interfacial area per unit volume of dispersion, in a gas-liquid contactor, for fractional hold up of gas = 0.1 and gas bubble diameter = 0.5 mm is given by (in m2/m3)

500

A

500

83
Q

Though, theoretically the adsorption & desorption isotherms is expected to coincide but sometimes at least a part of the isotherms does not coincide and this phenomenon is known as adsorption hysterisis. In such cases, the desorption equilibrium pressure is __________ that obtained for adsorption.

lower than

A

lower than

84
Q

Experiments were conducted to determine the flux of a species A in a stagnant medium across a gas-liquid interface. The overall mass transfer co-efficient based on the liquid side for dilute systems for the above was estimated to be 4 x 10-3 kg mole/m2.s. The equilibrium data for the system is given as y = 2x. The flux across the interface (in kg mole/m2 .s) for bulk concentrations of A in gas phase and liquid phase as y = 0.4 and x = 0.01 respectively is

A

8.5 x 10-4

85
Q

When an unsaturated air-water mixture is heated at constant pressure, then

the relative humidity decreases.

A

the relative humidity decreases.

86
Q

Mass transfer co-efficient is defined as

Co-efficient = Flux/concentration difference.

A

Co-efficient = Flux/concentration difference.

87
Q

At a fixed pressure, the humidity depends upon the partial pressure of vapor in the mixture. Humidity of a vapour free gas is __________ percent.

0

A

0

88
Q

The value of L/mG ratio for economical absorption operation ranges from

1.25 to 2.0

A

1.25 to 2.0

89
Q

Large scale usage of flash distillation is practised in

petroleum refinning

A

petroleum refinning

90
Q

Dried finished product sampled from various parts of a __________ dryer exhibits non-uniformity in the moisture content.

tray

A

tray

91
Q

Rotary dryers cannot handle __________ materials.

sticky

A

sticky

92
Q

A solid material shows case hardening properties while drying. Which of the following should be controlled to control the drying process ?

Temperature of the solid

A

Temperature of the solid

93
Q

When adsorption hysteresis is observed, the desorption equilibrium pressure is __________ that obtained by adsorption.

always lower than

A

always lower than

94
Q

Moisture in a substance exerting an equilibrium vapour pressure less than that of pure liquid at the same temperature is called the __________ moisture.

bound

A

bound

95
Q

Detergent solution is dried to a powder in a

spray dryer

A

spray dryer

96
Q

During bottling of cold drinks (e.g. Pepsi), the main resistance to mass transfer for the absorption of carbon dioxide in water lies in the

liquid film

A

liquid film

97
Q

The diffusivity (D) in a binary gas mixture is related to the temperature (T) as

D ∝ T1.5

A

D ∝ T1.5

98
Q

Tray spacing in a distillation column of dia 10-12 ft. used in petroleum refinery may be around __________ inches.

30

A

30

99
Q

A distillation column with N plates is being operated under normal conditions. At some point of time, the operation is shifted to total reflux condition (i.e., no product and residue are being withdrawn and feed to the column is stopped). At the new steady state,

the top and bottom compositions correspond to the maximum enrichment available.

A

the top and bottom compositions correspond to the maximum enrichment available.

100
Q

Dryer widely used in a textile industry is __________ dryer.

conveyor

A

conveyor

101
Q

Which of the following adsorbant is used in the refinning of sugar ?

Bone charcoal

A

Bone charcoal

102
Q

The dew point of an unsaturated gas-vapor mixture does not depend upon the __________ of the mixture.

temperature

A

temperature

103
Q

Removal of __________ exemplifies an adsorption unit operation.

water from petrol

A

water from petrol

104
Q

To remove all the moisture from a wet solid it requires exposure to __________ air.

perfectly dry

A

perfectly dry

105
Q

The operating cost of a distillation column at minimum reflux ratio is

minimum

A

minimum

106
Q

The reflux to a distillation column is 100 moles/hr, when the overhead product rate is 50 moles/hr. The reflux ratio is

2

A

2

107
Q

The wet and ‘dry bulb temperature for a vapour-gas mixture are 25°C and 30°C respectively. If the mixture is heated to 45°C at constant pressure, the wet bulb temperature will be __________ °C.

> 25

A

> 25

108
Q

Henry’s law states that the

partial pressure of a component over a solution is proportional to its mole fraction in the liquid.

A

partial pressure of a component over a solution is proportional to its mole fraction in the liquid.

109
Q

According to Poiseuille’s law, the permeability for gas flow through a capillary is proportional to (where, μ = gas viscosity)

1/μ

A

1/μ

110
Q

For a binary mixture distillation process, the degree of freedom is 2. However, if the pressure is fixed in this process, the number of independent variables in this process will be

1

A

1

111
Q

H2S is being absorbed in a gas absorber unit. The height of the transfer unit based on the overall mass transfer coefficient on the gas side is 0.4 m. The equilibrium data is given by, y = 1.5 x. The bulk concentration of H2S has to be reduced from 0.05 to 0.001 mole fraction in the gas side. The height of the tower (in metres) corresponding to an operating line given by, y = 5x + 0.001 is

2.0

A

2.0

112
Q

The most efficient cooling tower out of the following is

induced draft

A

induced draft

113
Q

Sodium bicarbonate is produced during soda ash manufacture using a __________ tower.

baffle

A

baffle

114
Q

The temperature of water cooled in cooling tower is always __________ temperature of entering air.

more than the wet bulb

A

more than the wet bulb

115
Q

Mass transfer co-efficient is directly proportional to DAB according to the __________ theory.

film

A

film

116
Q

Tower diameter may be decreased by

use of increased tray spacing.

A

use of increased tray spacing.

117
Q

Rayleigh’s equation applies to __________ distillation.

differential

A

differential

118
Q

The Reynolds number of the liquid was increased 100 fold for a laminar falling film used for gas-liquid contacting. Assuming penetrating theory is applicable, the fold increase in the mass transfer co-efficient (Kc) for the same sytem is

A

10

119
Q

The slope of 9-line is determined by the

thermal condition of the feed

A

thermal condition of the feed

120
Q

In steam distillation, the

product must be immiscible with water.

A

product must be immiscible with water.

121
Q

Which of the following can be calculated theoretically using steam table and Dalton’s law of partial pressure; if the relative humidity and dry bulb temperature of moist air is known ?

Wet bulb temperature

A

Wet bulb temperature

122
Q

A mixture of 10% C6H6 vapour in air at 25°C and 750 mm Hg has a dew point of 20°C. Its dew point at 30°C and 700 mm Hg will be around __________ °C.

18.7

A

18.7

123
Q

Moisture in a solid exerting an equilibrium vapour pressure equal to that of the pure liquid at the same temperature is called the __________ moisture.

Unbound

A

Unbound

124
Q

Refractory bricks are usually dried in a __________ dryer.

Tunnel

A

Tunnel

125
Q

What is the degree of freedom of an absorption process in which only one component is transferred between phases ?

3

A

3

126
Q

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

9

A

9

127
Q

Degree of freedom for leaching and solvent extraction process is

3

A

3

128
Q

An alkaline solution is used to reduce the concentration of carbon dioxide in a stream from 10% to 0.1% by absorption with irreversible chemical reaction. The overall number of transfer units based on gas phase is

4.605

A

4.605

129
Q

The adiabatic saturation curve for a vapour-gas mixture is

slightly concave upward.

A

slightly concave upward.

130
Q

Small dia distillation column can be a

__________ column is used in gas absorption process.

packed column

A

packed column

131
Q

An air-water vapour mixture has a dry bulb temperature of 60°C and a dew point temperature of 40°C. The total pressure is 101.3 kPa and the vapour pressure of water at 40°C and 60°C are 7.30 kPa and 19.91 kPa respectively.The humidity of air sample expressed as kg of water vapour/kg of dry air is

0.152

A

0.152

132
Q

In a moderately sized packed absorption tower, channeling (which is most severe with stacked packings) can be minimised by taking the ratio of tower diameter to packing diameter

> 8:1

A

> 8:1

133
Q

__________ column is preferred to be used, when a high liquid hold up is required in a reactor for gas-liquid reaction.

Bubble

A

Bubble

134
Q

Which of the following provides maximum contact surface for a liquid-vapour system?

Packed tower

A

Packed tower

135
Q

In stripping section of continuous distillation column, the

liquid is enriched with high boiler.

A

liquid is enriched with high boiler.

136
Q

In rectifying section of a continuous distillation column, the

vapour is enriched with high boilers.

A

vapour is enriched with high boilers.

137
Q

A pure drug is administered as a sphere and as a cube. The amount of drug is the same in the two tablets. Assuming that the shape and size do not influence the mass transfer, the ratio of rate of dissolution in water at t = 0 for the cubic to spherical tablet is

1.24

A

1.24

138
Q

In extraction, as the temperature increases, the area of hetrogeneity (area covered by binodal curve)

decreases

A

decreases

139
Q

In case of an unsaturated mixture of gas and vapor, the percentage saturation is __________ its relative saturation.

lower than

A

lower than

140
Q

Use of packed towers for distillation is generally limited to the

small sizes.

A

small sizes.

141
Q

For absorbing a sparingly soluble gas in a liquid, the

liquid side coefficient should be increased.

A

liquid side coefficient should be increased.

142
Q

Desulphurisation of petrol is done in a

rotating disc extractor

A

rotating disc extractor

143
Q

At 750°K and 1 atm, the approximate value of Schmidt number for air is

0.1

A

0.1

144
Q

Calculation of mass transfer co-efficient is mostly/normally done using __________ theory.

film

A

film

145
Q

Which of the following is used for the concentration of rubber latex ?

Agitated film evaporator

A

Agitated film evaporator

146
Q
A

DAY 2 (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions