# Separation Processes Questions and Answers – Algebraic Method for Determining N

«
»

This set of Separation Processes Multiple Choice Questions & Answers (MCQs) focuses on “Algebraic Method for Determining N”.

1. What does N stand for?
a) Number of processes
b) Number of stages
c) Number of equipment
d) Ratio of feed to product

Explanation: N stands for the number of stages corresponding to a cascade.

2. When does the graphical method become tedious?
a) When there are too many solvents
b) When too many stages are involved
c) When more than one solute is adsorbed or stripped
d) When the solute to be stripped is unknown

Explanation: The graphical method becomes tedious when more than one solute is adsorbed or stripped.

3. Which method is applied when graphical method is unsuitable?
a) Keller method
b) Newton’s method
c) Distillation method
d) Kremser method

Explanation: Kremser method is applied when graphical method is unsuitable.

4. What is the formula for fraction of the solute i absorbed?
a) A i N+1 – 1/ A i N+1 –A i
b) A i N+1 – A i / A i N+1 –1
c) S i N+1 – S i / S i N+1 –1
d) S i N+1 – A i / S i N+1 –1

Explanation: The formula for fraction of the solute I absorbed is A i N+1 – A i / A i N+1 –1 where A i = L/K i V.

5. What is the formula for fraction of the solute i stripped?
a) A i N+1 – 1/ A i N+1 –A i
b) A i N+1 – A i / A i N+1 –1
c) S i N+1 – S i / S i N+1 –1
d) S i N+1 – A i / S i N+1 –1

Explanation: The formula for fraction of the solute I stripped is S i N+1 – S i / S i N+1 –1 Where S i = K i V/L.

6. Which of the following does not give a correct expression for K i ?
a) Roult’s law
b) Henry’s law
c) Modified Roult’s law
d) Gas law

Explanation: The gas law is PV=nRT and it does not give an expression for K i .

7. When is the Roult’s law used?
a) Ideal solutions involving solutes at sub-critical temperatures
b) Non-ideal solutions involving solvents at sub-critical temperatures
c) Ideal solution involving solutes at critical temperatures
d) Non-ideal solutions involving solutes at critical temperatures

Explanation: The roullt’s law where K i = P s i /P is applied for Ideal solutions involving solutes at sub-critical temperatures.

8. Which equation is used for solutes at supercritical temperatures?
a) Roult’s law
b) Henry’s law
c) Modified Roult’s law
d) Gas law

Explanation: The henry’s law which is K i =H i /P is used for solutes at supercritical temperatures.

9. Which equation is sued for sparingly soluble solutes at sub-critical temperatures?
a) Roult’s law
b) Henry’s law
c) Modified Roult’s law
d) Solubility equation

Explanation: The solubility equation K i = P s i /x * i P is used for sparingly soluble solutes at sub-critical temperatures.

10. What is the formula for solute absorption factor?
a) Ai = LV/Ki
b) Si = Ki V/L
c) Ai =L/Ki V
d) Si = Ki /LV 