Question

Sulfuric acid in nitratil efuon mixture is useful to :

• A. Generate more amount of $N{O}_2^{+}$
• B. Generate less amount of $N{O}_2^{+}$
• C. decrease the protonation of $HN{O}_3$
• D. None

Answer 1

The correct option is A Generate more amount of $N{O}_2^{+}$

$N{O}_2^{+}$ is generated when water is eliminated from protonated nitric acid. Pure nitric acid contains only a small amount of $N{O}_2^{+}$. As a result, nitration with pure nitric acid proceeds only very slowly. However, strongly activated aromatic compounds may also be nitrated with nitric acid in a reasonable period of time. Nevertheless, a mixture of concentrated nitric acid and concentrated sulfuric acid, called nitrating acid, is usually applied to the nitration of aromatic compounds. Sulfuric acid is a stronger acid than nitric acid. Thus, protonation of nitric acid by sulfuric acid leads to a larger amount of $N{O}_2^{+}$ in nitrating acid than is obtainable in pure nitric acid. Hence option A is correct.