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# Separation Processes MCQ’s – Continuous Countercurrent Adsorption Systems

Which of the following is an advantage of using the continuous countercurrent operation?

a) Maximizes the average driving force for transport

b) Maximizes the efficiency

c) Maximizes the cost

d) Minimizes the cost

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Answer: a

Explanation: Countercurrent flow maximizes the average driving force for transport → increases adsorbent use efficiency.

What relationship is true about solute free mass flow rates?

a) F/S less than K less than D/S

b) D/S less than K less than F/S

c) F/S less than D/S less than K

d) D/S less than F/S less than K

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Answer: a

Explanation: F/S less than K less than D/S is true for solute free mass flow rates.

What is untrue for Mcabe thiele method for adsorption at elevated temperatures?

a) F/S cannot be greater than D/S

b) The two operating lines must intersect at the point (qR , cR )

c) Desorption line is placed below adsorption line by elevating temperature

d) Elevated pressure can also be used

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Answer: a

Explanation: F/S can be greater than D/S for Mcabe thiele method for adsorption at elevated temperatures.

If K_{A}= 20, K_{B}=30, what is the permissible values ,what is the safety margin for TMB model is:

a) 0-0.4

b) 0-0.81

c) 0.81-1

d) 0.9-1

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Answer: c

Explanation: Since the permissible range is between 1 and square root of K_{a}/K_{b}, the limit is square root of 20/30=0.81.

If K_{A}= 40, K_{B}=50, what is the permissible values ,what is the safety margin for TMB model is:

a) 0-0.4

b) 0-0.81

c) 0.81-1

d) 0.89-1

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Answer: d

Explanation: Since the permissible range is between 1 and square root of K_{a}/K_{b}, the limit is square root of 40/50=0.89.

If K_{A}= 20, K_{B}=80, what is the permissible values ,what is the safety margin for TMB model is:

a) 0-0.4

b) 1-0.5

c) 0.81-1

d) 0.9-1

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Answer: b

Explanation: Since the permissible range is between 1 and square root of K_{a}/K_{b}, the limit is square root of 20/80=0.5.

If K_{A}= 36, K_{B}=100, what is the permissible values ,what is the safety margin for TMB model is:

a) 1-0.6

b) 0-0.81

c) 0.66-1

d) 0.36-1

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Answer: a

Explanation: Since the permissible range is between 1 and square root of K_{a}/K_{b}, the limit is square root of 36/100=0.6.

If K_{A}= 50, K_{B}=60, what is the permissible values ,what is the safety margin for TMB model is:

a) 0-0.4

b) 1-0.89

c) 0.91-1

d) 0.97-1

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Answer: c

Explanation: Since the permissible range is between 1 and square root of K_{a}/K_{b}, the limit is square root of 50/60=0.91.

If K_{A}= 40, K_{B}=80, what is the permissible values ,what is the safety margin for TMB model is:

a) 0-0.5

b) 1-0.5

c) 0.70-1

d) 0.5-1

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Answer: c

Explanation: Since the permissible range is between 1 and square root of K_{a}/K_{b}, the limit is square root of 40/80=0.70.

If K_{A}= 10, K_{B}=60, what is the permissible values ,what is the safety margin for TMB model is:

a) 0-0.40

b) 1-0.167

c) 0.45-1

d) 0.407-1

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Answer: d

Explanation: Since the permissible range is between 1 and square root of K_{a}/K_{b}, the limit is square root of 10/60=0.40z.