Question

Assertion: Rectified spirit can be further purified by adding a dehydrating agent.
Reason: Addition of ${H_2}S{O_4}$ to 96% ethyl alcohol gives 100% ethyl alcohol.
What of the following is correct?
A.Both assertion and reason are correct and the reason is the correct explanation of assertion.
B.Both assertion and reason are correct and the reason is not the correct explanation of assertion.
C.Assertion is correct but reason is incorrect.
D.Both assertion and reason are incorrect.

Answer 1

Hint: Rectified spirit, also known as neutral spirits, rectified alcohol, or ethyl alcohol of agricultural origin is highly concentrated ethanol that has been purified by means of repeated distillation in a process called rectification. In some countries, denatured alcohol or denatured rectified spirit may commonly be available as "rectified spirit"

Complete answer:
A rectified spirit is a mixture with a composition of ethanol 95% and water with 5%. However, to attain a pure form of ethanol, one more separation step is required, so that the water content in the rectified spirit is removed completely. One was using quicklime (calcium oxide) to absorb water content and finally contacting the solution with anhydrous copper sulphate removes the leftover traces of water.
Absolute alcohol is named to 100% conc. ethanol. And rectified spirit is a mixture with a composition of 95% ethanol and 5% water. To attain a pure form of absolute alcohol, one more separation step is required, so that the water content in the rectified spirit is removed completely.
Hence, a Rectified spirit can be further purified by adding a dehydrating agent which is calcium oxide.

Hence, the assertion is CORRECT, but the reason is INCORRECT. (c) is correct.

Note:
The purity of rectified spirit has a practical limit of 95% ABV (95.6% by mass) when produced using conventional distillation processes, as a mixture of ethanol and water becomes a minimum boiling azeotrope at this concentration. Rectified spirit is typically distilled in continuous multi-column stills at 96–96.5% ABV and diluted as necessary.