Question

Absolute alcohol is prepared by the distillation of rectified spirit in the presence of:
\[
  A.{\text{ }}Na \\
  B.{\text{ }}CaC{O_2} \\
  C.{\text{ }}CaO \\
  D.{\text{ }}Ca{\left( {OH} \right)_2} \\
 \]

Answer 1

Hint- In order to deal with this question first we will define the term absolute alcohol then we will proceed further by understanding the process of manufacture of absolute alcohol by the distillation of rectified spirit.

Complete answer:
Absolute or anhydrous alcohol usually applies to pure ethanol, which comprises just one percent of gas. Absolute alcohol cannot be obtained by easy fractional distillation, since a mixture that comprises around 95.6 percent alcohol and 4.4 percent water is a continuous boiling mixture (an azeotropic mixture).
Distillation continues to be a tried and true method to separate water from ethanol. Distillation is a technique that's used to separate liquids from one another in a mixture and takes advantage of differing boiling points.
So, Absolute alcohol is prepared by the distillation of a rectified spirit in the presence of $CaO$ which absorbs water content and finally contacting the solution with anhydrous copper sulphate removes the leftover traces of water.
Hence, Absolute alcohol is prepared by the distillation of rectified spirit in the presence of $CaO$.

So, the correct answer is option C.

Note- Absolute ethanol finds use in a variety of applications, including medical, organic chemistry, and biology. It is also used as an alternative fuel source to gasoline for combustion engines. Medically, it is used as a solvent and injected into nerves and ganglia for relief of pain. Anhydrous ethanol is often used as an antiseptic to clean the scalp, often along with iodine, before injection.