# Distillation Design Questions and Answers – Simple Distillation

This set of Distillation Design Multiple Choice Questions & Answers (MCQs) focuses on “Simple Distillation”.

1. The overall Material balance, is given as
a) F = D+B
b) D =F +B
c) F = D+B
d) F=B-D

Explanation: F = B+D where F=Feed moles
D=Distillates
B= Bottoms moles.

2. The material Balance around a condenser, is given as
a) F = D+B
b) F = D+B
c) V = L+D
d) L= V + D

Explanation: V = L+D
V= Vapor from column
L= liquid returning to column.

3. For a batch distillation process
a) –ydV = d(xW)
b) –xdV = d(xW)
c) -xW =d(yV)
d)- yW =d(xV)

Explanation: –ydV = d(xW) where dV= vapor rate, moles/h
W=total moles in still.

4. The below equation, holds well for?

a) Flash distillation
b) Simple distillation
c) Multicomponent distillation
d) Final distillation

Explanation: This holds for simple distillation Where Wf=moles in the still and W0=moles originally charged.

5. If the integral part is given as -1.79 and still has 100 moles originally charged. Find the WF?
a) 15.8
b) 12.9
c) 16.7
d) 18.0

Explanation: As In WF100 = -1.79
So WF = 16.7.

6. Find α. If Xd=0.517 and Xw=0.3
a) 1.3
b) 2.5
c) 5.6
d) 3.4

Explanation: As α = Xd(1-Xw)/ Xw(1- Xd) using values we have 0.517(1-0.3)/0.3(1-0.517) = 2.5.

7. Calculate F? If D=4.61 and W=5.39
a) 7.8
b) 10
c) 9
d) 1.34

Explanation: As F = D +W = 4.61+5.39 = 10.

8. Calculate the enthalpy HF? If Cp= 0.825, W=32 and Tref=15C, at room temperature
a) 119 kcal/kmol
b) 78 kcal/kmol
c) 700 kcal/kmol
d) 70 kcal/kmol

Explanation: As Hf = (0.825) (32) (25-15) =119 kcal/kmol.

9. Batch distillation is also called as?
a) Flash distillation
b) Rayleigh’s Criteria
c) Thompson Distillation
d) Crane Distillation

Explanation: Batch distillation is also called as Rayleigh’s Criteria. As he invented it early 19th century, in this feed composition varies from time to time.

10. Flash distillation is called as?
a) Final distillation
b) Equilibrium distillation
c) Growth distillation
d) Full distillation

Explanation: Flash distillation is called as Equilibrium distillation because the volatility is the basis of the separation and will make components differ in mixture.

Sanfoundry Global Education & Learning Series – Distillation Design.
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