Mass Transfer Questions and Answers – Reflux Ratio Concept (Minimum, Maximun & Optimum)

This set of Mass Transfer Questions for entrance exams focuses on “Reflux Ratio Concept (Minimum, Maximun & Optimum)”.

1. If the reflux is total, minimum stages are used.
a) True
b) False
View Answer

Answer: a
Explanation: For total reflux no distillate formation; all the condensed vapour are sent back to fractionator.

2. At Total reflux
a) Residue is nil
b) Distillate is nil
c) Reflux is nil
d) All of the mentioned
View Answer

Answer: b
Explanation: Total reflux there condensed vapours are sent back to the column itself.

3. Reflux ratio is infinity at
a) Total reflux
b) Minimum reflux
c) Part reflux
d) None of the mentioned
View Answer

Answer: a
Explanation: Reflux ratio becomes infinity at distillate is equals to zero. Since reflux ratio = Reflux/distillate
At distillate = 0; Reflux ratio= infinity.
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4. Estimate the condenser requirement for total reflux.
a) Small condenser
b) Medium condenser
c) Large condenser
d) Partial condenser
View Answer

Answer: c
Explanation: Since if the large condenser are used, vapour gets condensed and becomes reflux where distillate is zero.

5. For minimum reflux ratio the number of trays becomes infinite.
a) True
b) False
View Answer

Answer: a
Explanation: For minimum reflux ratio, all the condensed vapour becomes distillate; no reflux. So it requires infinite number of trays.
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6. For a minimum reflux ratio ________ condenser or reboiler loads are used.
a) Less
b) More
c) Infinity
d) Partial
View Answer

Answer: a
Explanation: Since for minimum reflux ratio no reflux is produced, it’s enough to use minimum load condenser or reboiler.

7. Find the representation X.
The condensed vapours are refluxed (no distillate)
a) Partial condenser
b) Total condenser
c) Reboiler
d) None of the mentioned
View Answer

Answer: b
Explanation: All the condensed vapours are refluxed (no distillate).
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8. For finding the exact number of trays the reflux ratio should be between minimum and infinity.
a) True
b) False
View Answer

Answer: a
Explanation: The minimum trays cannot be determined; also infinite trays are impossible; so the trays should be minimum and infinity.

9. The reflux ratio increases by increasing the reflux and decreasing the distillate.
a) True
b) False
View Answer

Answer: a
Explanation: Reflux ratio= reflux/distillate.
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10. Find the co-relation of the representation.
The co-relation of the representation is Minimum reflux ratio
a) Maximum reflux ratio
b) Optimum reflux ratio
c) Minimum reflux ratio
d) None of the mentioned
View Answer

Answer: c
Explanation: Since there is no reflux, all the condensed vapours are distillate. Then it represents minimum reflux ratio.

Sanfoundry Global Education & Learning Series – Mass Transfer.

To practice all areas of Mass Transfer for entrance exams, here is complete set of 1000+ Multiple Choice Questions and Answers

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]

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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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