1. How will you separate o-Xylene and m-Xylene products of the same compounds?
a) Crystallization
b) Distillation
c) Polymer membrane
d) Electrophoresis
Explanation: The above mentioned components have same boiling points. So distillation cannot be used. Since they have a difference in melting point, crystallization is used.
2. How is Oil and Hexane separated?
a) Distillation
b) Separating funnel
c) Crystallization
d) Electrophoresis
Explanation: Oil and Hexane will have huge differences in the molecular weights. Hence they will form two phases in a separating funnel. Thus the layer that settles down can be removed. Distillation cannot be used here because oil might get damaged.
3. How a mixture of isopropyl alcohol and water is be separated?
a) One step distillation
b) Two step distillation
c) Two step crystallization
d) Separating funnel
Explanation: A two-step distillation is employed where there is an addition of benzene which is soluble in IPA and thus forms a layer. Now IPA and benzene mixture can be separated from water using a separating funnel. Further distilling, we get benzene and IPA.
4. How a mixture of iron and copper fillings is be separated?
a) Magnetic separation
b) Crystallization
c) Evaporation
d) Distillation
Explanation: Magnetic separation is employed since the components have difference in magnetic properties
5. How can the DNA fragments be separated from DNA?
a) Crystallization
b) Electrophoresis
c) Distillation
d) Zone melting
Explanation: DNA fragments migrate to positive electrode in the electric field
6. 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.
7. 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.
8. Which separation process is used when the volatility differences is too small between the species?
a) Flash vaporization
b) Stripping
c) Extractive distillation
d) Liquid-Liquid extraction
Explanation: Extractive distillation is used where a miscible MSA increases the volatility difference between the components.
9. What is added when it is difficult to condense vapors leaving the distillation column at top?
a) Adsorbent
b) Absorbent
c) Agitator
d) ESA
Explanation: The absorbent help to condense the vapor leaving the distillation column.
10. Which separation technique shall be used to remove ethane and lower molecular weight hydrocarbons for LPG production?
a) Flash vaporization
b) Distillation
c) Reboiled absorption
d) Stripping
Explanation: Reboiled absorption shall be used since it is difficult to condense the ethane vapors leaving from the top.