Chapter 15, Problem 21P

Interpretation Introduction

Interpretation: The major product formed when each of the given compound reacts with a mixture of concentrated $HN{O}_3$ and $H_{2}S{O}_4$.

Concept introduction:

When an aromatic compound reacts concentrated $HN{O}_3$ and $H_{2}S{O}_4$, the reaction is called nitration.

Nitration is an electrophilic aromatic substitution reaction.

Para substitution is more stable over ortho due to steric hindrance at the ortho position.

Activating groups like alkyl groups, $-N{H}_2,-OH$ gives substitution at the ortho and para position. Because they increase the electron densities at the ortho and para due to the delocalization of pi electrons of benzene ring. Ortho and para sites of the benzene ring is highly electron rich, and thus, electrophile usually attacks on these sites.

Deactivating group gives substitution at the meta position. Such electron withdrawing group gives stable product at meta position.