250+ TOP MCQs on Distillation – Partial Pressure and Answers

Food Processing Unit Operations Multiple Choice Questions & Answers on “Distillation – Partial Pressure”.

1. How to calculate partial pressure?
a) Sum of the pressures of each individual gas
b) Total pressure multiplied by the mole fraction of that gas
c) Sum of the mole fraction of each individual gas
d) Total concentration multiplied by the mole fraction of that gas
Answer: b
Clarification: The total pressure of the mixture of gases is the sum of the individual pressures of each gas. The partial pressure of an individual gas is equivalent to the total pressure multiplied by mole fraction of that individual gas.

2. What is the use of partial pressure?
a) To predict the movement of gases
b) To predict the concentration change
c) To predict the pressure change
d) To predict the mole fraction
Answer: a
Clarification: Partial pressure is the force exerted by a gas. Partial pressure is very important in predicting the movement of gases.

3. What is partial pressure of water vapor?
a) 23.8 mm Hg
b) 230.8 mm Hg
c) 2.38 mm Hg
d) 0.238 mm Hg
Answer: a
Clarification: The water vapor pressure is the partial pressure of water vapor in any gas mixture in equilibrium with solid or liquid water.

4. What is r value in pV= nRT?
a) 0.8314 J/mol•K
b) 831.4 J/mol•K
c) 83.14 J/mol•K
d) 8.314 J/mol•K
Answer: d
Clarification: The ideal gas law is pV = nRT, where n is the number of moles, and R is universal gas constant. The value of R depends on the units involved, and S.I. unit is 8.314 J/mol•K.

5. Which of the following component is constant in Boyle’s law?
a) Concentration
b) Pressure
c) Temperature
d) Volume
Answer: c
Clarification: At constant temperature, the volume of a given mass of a dry gas is indirectly proportional to its pressure is known as Boyle’s law.

6. Does partial pressure depend on temperature?
a) True
b) False
Answer: a
Clarification: As temperature increases the molecular activity at the surface of the water also increases. An increase in temperature would increase the partial pressure where the volume of the container remains constant.

7. What is the limitation of Dalton’s law?
a) It implies only for real gases at low pressure
b) It implies only for real gases at high pressure
c) It implies only for real gases at low concentration
d) It implies only for real gases at high concentration
Answer: a
Clarification: The Dalton’s law is good for real gases at low pressure, but at high pressure, it deviates considerably. The mixture of gases is non-reactive in nature. Another assumption is that the interaction between each individual gas molecules is same as the molecules in the mixture.

8. Which of the following statements about partial pressure are correct?
Statement 1: The partial pressure of each gas in a mixture is not proportional to its mole fraction..
Statement 2: The partial pressure of each gas is the product of the total pressure and the mole fraction of that gas.
a) True, False
b) True, True
c) False, True
d) False, False