Question

. P and Q can be separated by fractional distillation. The boiling points of
P and Q are _____ and _______ respectively.
A. 329 K and 473 K
B. 329 K and 354 K
C. 329 K and 332 K
D. 329 K and 373 K

Answer 1

• If the difference in boiling point is below 25° C  or 25 K, simple distillation can not be used to separate them rather fractional distillation has to be used.

• In this method, vapours of a liquid mixture are passed through a fractionating column before condensation.

• The fractionating column is fitted over the opening of the round bottom flask.

• Vapours of the liquid of higher boiling point condense before that of the lower boiling point.

Here, in the third option the difference  is of 3 K which is less than 25K .

So, the correct answer will be option c.

Answer 2

• As we know that If the difference in boiling point is below 25° C  or 25 K, simple distillation can not be used to separate them rather fractional distillation has to be used.
• And the vapors of a liquid mixture are passed through a fractionating column before condensation.
• So, The fractionating column is fitted over the opening of the round bottom flask.
• We know that the Vapors of the liquid of a higher boiling point condense before that of the lower boiling point.
• Then in the third option, the difference is 3K which is less than 25K.

Hence, the correct answer will be option c.