Question

Primary amines can be converted into alcohols by the action of
(A) Alkali
(B) Nitrous acid
(C) Reducing agent
(D) Oxidising agent

Answer 1

Hint: Primary amines are the amines in which the N of $N{{H}_{2}}$ group is attached to only one carbon. In the conversion of primary amines to alcohol, the amine $(-N{{H}_{2}})$ functional group is replaced by a hydroxyl ($-OH$) group.

Complete Step by Step Solution:
A primary amine can be converted into alcohol by the action of nitrous acid ($NaN{{O}_{2}}$ +$HCl$) on it. When nitrous acid ($NaN{{O}_{2}}$ +$HCl$) is treated with primary amines at a low temperature (273K – 278K), it gives rise to diazonium salt. When this diazonium salt is hydrolysed or treated with dilute acid, it forms alcohol. Along with the alcohol, side products like nitrogen (${{N}_{2}}$ ) gas and hydrochloric acid ($HCl$ ) are also formed.

Correct Option: (B) Nitrous acid.

Additional Information: Alcohols have a wide range of applications in our daily lives. The paper we use for writing, the sugar we eat, and the sanitizers that we use to disinfect our hands are all made up of compounds that contain hydroxyl groups. The alcohols are soluble in water due to their ability to form hydrogen bonds in water. However, this solubility decreases with an increase in the size of alkyl or aryl groups.

Note: The well-known trihydric alcohol, glycerol ($C{{H}_{2}}(OH)-C{{H}_{2}}(OH)-C{{H}_{2}}(OH)$ )(IUPAC Name-Propane-1,2,3-triol) has various uses. It is used for the treatment of constipation. It can also be used as a solvent for flavours and food colours and for improving the performance of athletes.