Chemical Process Calculation Multiple Choice Questions & Answers (MCQs) focuses on “Saturation”.
1. Antoine equation is a relation between
a) Vapour pressure and partial pressure
b) Vapour pressure and Temperature
c) Vapour pressure and absolute pressure
d) None of the mentioned
Answer: b
Clarification: Antoine equation is a relation between Vapour pressure and Temperature.
2. Correct representation of the Antoine equation is
a) ln(p*) = A-B/(C+T)
b) log(p*) = A-B/(C-T)
c) ln(p*) = A+B/(C+T)
d) log(p*) = A-B/(C+T)
Where: p* & T are Vapour pressure and Temperature respectively and A, B & C are constants.
Answer: b
Clarification: ln(p*) = A-B/(C+T) is the correct representation of Antoine equation.
3. The temperature at which the vapour just start to condense at a specified pressure is
a) Critical temperature
b) Boiling point
c) Dew point
d) Triple point
Answer: c
Clarification: The temperature at which the vapour just start to condense at a specified pressure is Dew point.
4. At dew point the partial pressure of the is equal to the partial pressure of the volatile liquid.
The above given statements is
a) Always correct
b) Incorrect
c) Depends on the properties of the liquid
d) None of the mentioned
Answer: b
Clarification: At dew point the partial pressure of the is equal to the vapour pressure of the volatile liquid.
5-7. Assume water in air at 600 mm of Hg at 51 Degree Celsius. (Vapour pressure = 98 mm Hg)
5. What is the pressure of Air?
a) 502 mm Hg
b) 402 mm Hg
c) 302 mm Hg
d) 202 mm Hg
Answer: a
Clarification: Pair = Ptotal – p*.
6. What is the composition of vapour?
a) 0.163
b) 0.183
c) 0.2837
d) 0.8367
Answer: a
Clarification: yH2O = 98/600.
7. What is the composition of vapour?
a) 0.163
b) 0.183
c) 0.2837
d) 0.8367
Answer: d
Clarification: yAir = 502/600.
8. Dew point of water at standard conditions is?
a) 100 K
b) 273 K
c) 373 K
d) 473 K
Answer: c
Clarification: Dew point of water at standard condition = 100 Degree Celsius.
9-10. Water vapour of 5 KPa at 300 K is saturated with air in a system.
9. What is the mole fraction of air?
a) 0.952
b) 0852
c) 0.259
d) 0.291
Answer: a
Clarification: Mole fraction of air = 101.3/(5 + 101.3) = 0.952.
10. What is the mole fraction of vapour?
a) 0.047
b) 0.057
c) 0.067
d) 0.077
Answer: a
Clarification: Mole fraction of air = 5/(5 + 101.3) = 0.047.