Question

Replacement of $Cl$ of $\text{chlorobenzene}$ to give phenol requires drastic conditions but $Cl$ of $2,4-\text{dinitrochlorobenzene}$ is readily replaced. This is because:

• A. $N{O}_2$ makes the ring electron rich at ortho and para positions
• B. $N{O}_2$ withdraws electron from meta-position
• C. $N{O}_2$ donates electron at m-position
• D. $N{O}_2$ withdraws electrons from ortho/para-positions

Answer 1

The correct option is D $N{O}_2$ withdraws electrons from ortho/para-positions

$-N{O}_2$ group is electron withdrawing group and it decreases electron density at ortho and para positions. So a nucleophile is attracted to more electron deficient substrate and hence nucleophilic substitution becomes easier and hence replcement of $Cl$ becomes easier.