Separation Processes

Question 1

A unit operation in which a soluble component is removed from an inert solid by a solvent which preferentially dissolves the soluble matter is known as

Answer 1

Leaching

Question 2

The unit operation by which soluble components of a liquid mixture are dissolved in a liquid immiscible with the insoluble component is

Answer 2

Solvent extraction

Question 3

Tea percolation employs

Answer 3

Leaching

Question 4

Most commonly used leaching solvent in vegetable oil industry

Answer 4

Hexane

Question 5

Leaching of sugar from sugar beets is done using

Answer 5

Hot water

Question 6

In a counter-current extractor, as the axial mixing increases, the extraction efficiency

Answer 6

Decreases

Question 7

Bollman extractor

Answer 7

Is used for extraction of oil from oilseed

Question 8

Radioactive nuclear waste is treated in

Answer 8

Pulsed column extractor

Question 9

Acetic acid will be most economically separated from a dilute solution of acetic acid in water by

Answer 9

Solvent extraction

Question 10

Liquid-liquid extraction is based on the differences in

Answer 10

Solubility

Question 11

The solvent used in liquid extraction should not have high latent heat of vaporization, because

A. the pressure drop and hence the pumping cost will be very high.
B. it cannot be recovered by distillation.
C. its recovery cost by distillation may be prohibitively high.
D. it will decompose while recovering by distillation.

Answer 11

C. its recovery cost by distillation may be prohibitively high.

Question 12

Solvent extraction is the terminology applied to the liquid-liquid extraction, which is preferred for the separation of the components of liquids, when

A. extracting solvent is cheaply and abundantly available.
B. one of the liquid components is heat sensitive.
C. viscosity of liquid components is very high.
D. one of the liquid components has very high affinity towards the solvent.

Answer 12

A. extracting solvent is cheaply and abundantly available

Question 13

In a counter-current liquid extractor

A. both liquids flow at fixed rate.
B. both liquids can have any desired flow rate.
C. only one of the liquids may be pumped at any desired rate.
D. liquid’s flow rate depends upon the temperature and pressure.

Answer 13

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

Question 14

A coalescer in a mixer-settler liquid-liquid extraction column

A. comprises of thin bed of substances of extended surface having high porosity.
B. helps in increasing the bubble size entering the settler.
C. helps in increasing the settling rate of the bubbles.
D. all of these

Answer 14

D. all of these

Question 15

Antibiotics are best handled in a

Answer 15

Podbielniak extractor

Question 16

Which of the following solutions will follow Raoult’s
law most closely?

A. A solution of benzene, toluene and oxylene
B. 35% solution of camphor in water
C. 35% solution of NH3 in water
D. A solution of polar organic compounds (not of homologs of a series).

Answer 16

A. A solution of benzene, toluene and oxylene

Question 17

Boiling point diagram is

Answer 17

Affected by pressure

Question 18

The ease of difficulty of separating components by distillation is determined by the

Answer 18

relative volatility

Question 19

Strictly speaking, the relative volatility of most
ideal binary solution is

Answer 19

greatly affected by temperature

Question 20

When the relative volatility of two miscible components is close to 1.00, the components can be separated by

Answer 20

extractive distillation

Question 21

The physical separation of components in a miscible mixture by simultaneous evaporation and condensation is

Answer 21

Distillation

Question 22

In a batch distillation, the boiling point of the distillate product compared to the residue is

Answer 22

Lower

Question 23

Increasing the operating pressure distilling column

Answer 23

makes separation difficult

Question 24

One mole feed of a binary mixture of a given composition is flash vaporized at a fixed P and T. If Raoult’s law is obeyed, then changing the feed composition would effect

A. the product composition but not the fraction vaporized.
B. the product composition as well as the fraction vaporized.
C. the fraction vaporized but not the product composition.
D. neither the product composition nor the fraction vaporized.

Answer 24

C. the fraction vaporized but not the product composition

Question 25

Steam distillation is used to

Answer 25

avoid thermal decomposition of a component.

Question 26

The amount of steam required per unit quantity of distillate in case of steam distillation will be reduced by

A. raising the temperature
B. lowering the total pressure
C. both (a) and (b)
D. neither (a) nor (b)

Answer 26

C. both (a) and (b)

Question 27

In distillation, the cooled liquid stream returned to the column to a cool plate or stage is called

Answer 27

Reflux

Question 28

In a distilling column, the highest pressure will be at

Answer 28

The bottom

Question 29

A heat transfer equipment to convert vapor to liquid is a/an

Answer 29

Condenser

Question 30

A reboiler provides heat to the

Answer 30

the bottom of a distilling column

Question 31

The temperature in distilling column, from bottom to top

Answer 31

Decreases

Question 32

The theoretical minimum reflux ratio in distillation column is attained if the column has

Answer 32

Infinite number of plates

Question 33

As the reflux ratio decreases, the

Answer 33

Number of plates increases.

Question 34

In a distillation column, with increase in the reflux ratio, the heat removed in the cooler

Answer 34

Increases

Question 35

Fenske’s equation for determining the minimum number of theoretical stages in distillation column holds good, when the

Answer 35

relative volatility is reasonably constant.