1. Which separation technique shall be employed to separate acetone and methanol?
a) Extractive distillation
b) Stripping
c) Liquid-Liquid extraction
d) Evaporation
Explanation: Extractive distillation shall be used here since the volatility difference is very small.
2. In azeotropic distillation, why is an entrainer added?
a) To increase the boiling point of the mixture
b) To decrease the boiling point of the mixture
c) To form a minimum boiling point azeotrope
d) To form two immiscible phases
Explanation: In the separation of acetic acid with water, -butyl acetate is added which acts as an entrainer and forms two liquid, minimum boiling point azeotrope with water. It is then overhead and condensed and separated in acetate and water layers.
3. When is the liquid-liquid extraction preferred over distillation?
a) When the distillation apparatus is not available
b) Distillation apparatus is costly
c) When there too very high difference in the boiling points.
d) When the liquid mixture is temperature sensitive
Explanation: When the liquid mixture is temperature sensitive, liquid-liquid extraction is used by adding a solvent that selectively dissolves in one of the liquids.
4. Which of the following solvents can be added during separation of Isopropyl alcohol and water?
a) Methanol
b) Ethanol
c) Benzene
d) Alcoholic KOH
Explanation: Benzene selectively dissolves in IPA and thus two layers are formed which can be separated using a separating funnel
5. How is sulphur separated from its impurities?
a) Desublimation
b) Sublimation
c) Crystallization
d) Drying
Explanation: Sublimation is the technique used since sulphur can be sublimed and then condensed.
6. Where is the technique of leaching used?
a) Research laboratories
b) Soap industry
c) Pharmaceutical industry
d) Metallurgical industry
Explanation: Leaching is used in extraction of metals in metallurgical industry.
7. What is the semi-permeable membrane used in separation techniques made from?
a) Animal calls
b) Plant cells
c) Egg shells
d) Natural fibers
Explanation: Natural fibers act best as semi-permeable membrane
8. What is separation effected by in microporous membranes?
a) Difference in solubility
b) Rate of species diffusion through the pores
c) Amount of feed to the membranes
d) Number of membranes used
Explanation: Rate of species diffusion through the pores.
9. What is separation effected by in non-porous membranes?
a) Differences In solubility in the membrane
b) Rate of species diffusion through the pores
c) Amount of feed to the membranes
d) Number of membranes used
Explanation: The differences in solubility lead to the separation in case of non-porous membranes.
10. What is meant by osmosis?
a) A process where molecules of a solute travel from more concentrated solution to less concentrated solution
b) A process where molecules of solute travel from less concentrated solution to more concentrated solution
c) A process where molecules of solvent travel from less concentrated solution to more concentrated solution through a semi-permeable membrane
d) A process where molecules of solvent travel from more concentrated solution to less concentrated solution through a semi-permeable membrane
Explanation: The solvent travels from less concentration to more concentration thus equalizing the ncentration.This process is called as osmosis.