250+ TOP MCQs on Deviation from Idealities Concept and Answers

Mass Transfer MCQs on “Deviation from Idealities Concept”.

1. Given the total pressure is 2 atm. Also the partial pressure of the two components in an ideal solution is 1 atm and 0.5 atm. It shows __________ deviation.
a) Positive
b) Negative
c) Neutral
d) None of the mentioned
Answer: a
Clarification: If the total pressure is greater than sum of partial pressure then it shows positive deviation.

2. If the vapour pressure of the two components in a binary mixture is same, then it is a________
a) Isotope
b) Azeotrope
c) Differential boiling point
d) None of the mentioned
Answer: b
Clarification: Azeotrope is a mixture with a same boiling point.

3. Minimum boiling azeotrope has_________
a) Large positive deviation
b) Less positive deviation
c) Large negative deviation
d) Less negative deviation
Answer: a
Clarification: The difference of vapour pressure is large it shows large positive deviation.

4. Alternative word of Azeotrope is a Differential-boiling point.
a) True
b) False
Answer: b
Clarification: Azeotrope is a constant boiling mixture since it component has the same boiling point.

5. Express the point A

a) Vapour pressure of the high volatile component
b) Vapour pressure of the low volatile component
c) Pure component B
d) None of the mentioned
Answer: b
Clarification: Since there is a low vapour pressure at the point A, it the representation of low volatile component.

6. Negative deviation is due to a total pressure less than the pressure obtained from Hendry’s law.
a) True
b) False
Answer: b
Clarification: Because the total pressure should be less than the pressure obtained from Rauolt’s law.

7. Azeotropic composition can be eliminated by
a) Changing pressure
b) Changing temperature
c) Changing volume
d) None of the mentioned
Answer: a
Clarification: As by changing the vapour pressure we can avoid the azeotropic composition because the Azeotrope formation is due to same vapour pressure of the components.

8. When the two liquid mixtures are completely insoluble then the total pressure of the mixture is
a) Sum of the vapour pressure
b) Sum of the partial pressure
c) Pressure cannot be determined
d) None of the mentioned
Answer: a
Clarification: If the mixture is soluble the partial pressure comes to the part.No liquid exist without pressure. Therefore, the pressure of the mixture can be determined by the sum of its vapour pressure as this concept is mostly useful for stream distillation.

9. Consider an insoluble mixture A and B; Find the Total pressure of the system
Vapour pressure of A= 50mmHg
Vapour pressure of B= 100 mmHg
a) 50 mmHg
b) 100 mmHg
c) 150 mmHg
d) 200 mmHg
Answer: c
Clarification: For an insoluble mixture, total pressure = sum of vapour pressure.

10. Ordinary distillation cannot separate Azeotrope.
a) True
b) False
Answer: a
Clarification: For same vapour pressure (Azeotrope), it is not possible to separate by ordinary distillation for that we need azeotropic or extractive distillation.