What is the role of $\mathrm{HNO}_3$ in the nitrating mixture used for nitration of benzene?
$\mathrm{HNO}_3$ acts as a base in the nitrating mixture and provide the electrophile, $\mathrm{NO}_2^{+}$on reaction with $\mathrm{H}_2 \mathrm{SO}_4$ as follows
$$\mathrm{\mathop {HN{O_3}}\limits_{Base} + \mathop {{H_2}S{O_4}}\limits_{Acid} \buildrel {} \over \longrightarrow \mathop {{H_2}N{O_3}}\limits_{conjugate\,acid} + HSO_4^ - \buildrel {} \over \longrightarrow \mathop {NO_2^ + }\limits_{Electrophile} + HSO_4^ - + {H_2}O}$$
Why is $\mathrm{NH}_2$ group of aniline acetylated before carrying out nitration?
In order to check the activation of benzene ring by amino group, first it is acetylated with acetic anhydride or acetyl chloride in presence of pyridine to form acetanilide which can be further nitrated easily by nitrating mixture.
What is the product when $\mathrm{C}_6 \mathrm{H}_5 \mathrm{CH}_2 \mathrm{NH}_2$ reacts with $\mathrm{HNO}_2$ ?
$\mathrm{C}_6 \mathrm{H}_5 \mathrm{CH}_2 \mathrm{NH}_2$ on reaction with $\mathrm{HNO}_2$ produces $\mathrm{C}_6 \mathrm{H}_5 \mathrm{CH}_2 \mathrm{~N}_2^{+} \mathrm{Cl}^{-}$as follows
What is the best reagent to convert nitrile to primary amine?
Best reagent to convert nitrile to aniline is sodium/alcohol or $\mathrm{LiAlH}_4$.
Give the structure 'A' in the following reaction.
Complete conversion can be shown as
