LIQUID-LIQUID EXTRACTION

Question 1

Acetic acid will be most economically separated from a dilute
solution of acetic acid in water by
a. solvent extraction c. continuous distillation
b. evaporation d. absorption

Answer 1

a. solvent extraction

Question 2

Liquid-liquid extraction is based on the differences in
a. solubility c. partial pressure
b. specific volume d. viscosity

Answer 2

a. solubility

Question 3

Which method is more efficient, a single large washing or
repeated small washing?
a. single large washing
b. repeated small washing
c. both a and b
d. either a or b

Answer 3

b. repeated small washing

Question 4

A solution of solute (A) in diluent (B) is mixed with solvent (S).
The component (B) is slightly soluble in (S). The resulting
extract will be
a. rich in S, poor in B, poor in A
b. poor in S, rich in B, poor in A
c. rich in S, rich in B, rich in A
d. rich in S, poor in B, rich in A

Answer 4

d. rich in S, poor in B, rich in A

Question 5

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 5

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

Question 6

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 & 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 6

a. extracting solvent is cheaply & abundantly available.

Question 7

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 7

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

Question 8

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 8

d. all of these

Question 9

Antibiotics are best handled in a
a. Podbielniak extractor
b. rotating disc contactor
c. sieve tray contractor
d. pulsed column extractor

Answer 9

a. Podbielniak extractor