A. Azeotropic mixture is to be separated and the final product is miscible with water
B. Liquids decompose, if distilled directly at atmospheric pressure
C. Material cannot be distilled by indirect heating even under low pressure, because of the high
boiling temperature
D. Material to be distilled is thermally unstable or has the tendency to react with other
components associated with it, at the boiling temperature
Related Mcqs:
- 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. - If the amount of the steam used in steam distillation is increased, the temperature of distillation__________________?
A. Increases
B. Decreases
C. Remains unchanged
D. Depends on relative volatility - In case of steam distillation, the steam leaving the liquid is not completely saturated with distillate vapour, because_______________?
A. Temperature is less
B. Total pressure is less
C. Mixing of steam with the material being vaporised is not so intimate as to result in equilibrium
condition
D. Saturated steam is used for steam distillation - In steam distillation, the _____________________?
A. Temperature is 100°C
B. Temperature is more than 100° C
C. Product must be immiscible with water
D. Temperature is higher than the boiling point of either component - Polar organic compounds are normally used as separating agents for the azeotropic and extractive distillation. Which of the following is the most important factor to be considered for the choice of the separating agent for extractive distillation ?
A. Cost
B. Availability
C. Toxicity
D. Selectivity - Steam distillation is used to__________________?
A. Reduce the number of plates
B. Avoid thermal decomposition of a component
C. Increase the efficiency of separation
D. Increase the total pressure of distillation - Steam distillation is used for separation of high boiling ____________________?
A. Substances from non-volatile impurities
B. Volatile impurity from still higher boiling substances
C. Both A. and B.
D. Neither A. nor B. - An aqueous solution of methanol is to be distilled in a tray column. High pressure steam is available as a source of heat. For a given reflux ratio and overhead composition, two options are being explored; (i) a reboiler is used and (ii) no reboiler is used but steam is fed directly to the bottom of the column. As compared to option (i), in option (ii) ____________________?
A. Less number of trays are required
B. Composition of the residue remains unchanged
C. More number of trays are required but the residue composition remains unchanged
D. More number of trays are required and the residue composition is more dilute in methanol - Flash distillation is suitable for separating the constituents of a binary system, which _____________________?
A. Form minimum boiling azeotrope
B. Have very wide boiling points
C. Have very close boiling points
D. Form constant boiling azeotrope - Overall efficiency of the distillation column is _____________________?
A. The ratio of number of ideal plates to actual plates
B. The ratio of number of actual plates to ideal plates
C. Same as the Murphree efficiency
D. Always more than the point efficiency
