Question

In the following set of aromatic compounds

The correct order of reactivity toward Friedel-Crafts alkylation is

• A. i > ii > iii > iv
• B. ii > iv > iii > i
• C. iv > ii > iii > i
• D. iii > i > iv > ii

Answer 1

Answer: (C)

The electron releasing groups attached to benzene increases the reactivity towards Friedel-Crafts alkylation whereas the electron withdrawing groups decreases the reactivity.
Among the given groups, $-N{O}_2$ and $COOC{H}_3$ are electron withdrawing group EWG, so they will decrease the reactivity where $N{O}_2$ shows stronger $-I$ effect than $COOC{H}_3.$ So, the reactivity of nitrobenzene towards Friedel-Craft alkylation will be least. $OC{H}_3$ is an electron donating group, so it will increasing the reactivity.
Thus, the order of reactivity towards Friedel-Craft alkylation is
(iv) > (ii) > (iii) > (i)