Engineering Questions with Answers - Multiple Choice Questions
Separation Processes MCQ’s – separations by Phase Additions or Creations
1 - Question
What is the role of Energy-separating agent (ESA)?
a) Involves heat transfer
b) Involves mass transfer
c) Acts as an agitator
d) Is a catalyst
Explanation: The role of ESA is to perform heat transfer. Example: Creation of vapor from liquid phase by reducing pressure.
2 - Question
Which of the following is NOT a disadvantages of using a mass-separating agent (MSA) ?
a) Need for additional separator to remove MSA
b) Possible MSA contamination
c) Difficult design procedures
d) Need for large quantities of MSA
Explanation: There is no need for large quantities of MSA and the quantities are defined by the amount of feed.
3 - Question
Which separation process is used when the volatility differences is too small between the species?
a) Flash vaporization
c) Extractive distillation
d) Liquid-Liquid extraction
Explanation: Extractive distillation is used where a miscible MSA increases the volatility difference between the components.
4 - Question
What is added when it is difficult to condense vapors leaving the distillation column at top?
Explanation: The absorbent help to condense the vapor leaving the distillation column.
5 - Question
Which separation technique shall be used to remove ethane and lower molecular weight hydrocarbons for LPG production?
a) Flash vaporization
c) Reboiled absorption
Explanation: Reboiled absorption shall be used since it is difficult to condense the ethane vapors leaving from the top.
6 - Question
Which separation technique shall be employed to separate acetone and methanol?
a) Extractive distillation
c) Liquid-Liquid extraction
Explanation: Extractive distillation shall be used here since the volatility difference is very small.
7 - Question
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.
8 - Question
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.
9 - Question
Which of the following solvents can be added during separation of Isopropyl alcohol and water?
d) Alcoholic KOH
Explanation: Benzene selectively dissolves in IPA and thus two layers are formed which can be separated using a separating funnel.
10 - Question
How is sulphur separated from its impurities?
Explanation: Sublimation is the technique used since sulphur can be sublimed and then condensed.
11 - Question
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.