Give reasons for the following: (i) tert-butylbenzene does not give benzoic acid on treatment with acidic KMnO4. (ii) Normally, benzene gives electrophilic substitution reaction rather than electrophilic addition reaction although it has double bond.

Question

Give reasons for the following: (i) tert-butylbenzene does not give benzoic acid on treatment with acidic KMnO4. (ii) Normally, benzene gives electrophilic substitution reaction rather than electrophilic addition reaction although it has double bond. (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

(i) Oxidation of side-chain alkyl group of benzene occur through free radical mechanism and it initiates ata-C as.
In tertiary butyl benzene, there is nooc-H, required to initiate free radical oxidation reaction, hence not oxidised with

K M n O_{4}

.
(ii) Pi-electrons of double bonds are involved in aromatic delocalisation (aromaticity), hence electrophilic addition do not occur as it would destroy aromatic stability. However, electrophilic substitution do not destroy aromaticity.

Q. Give reasons for the following : (i) tert-butylbenzene does not give benzoic acid on treatment with acidic KMnO4​. (ii) Normally, benzene gives electrophilic substitution reaction rather than electrophilic addition reaction although it has double bond.

Q. Give reasons for the following :
(i) tert-butylbenzene does not give benzoic acid on treatment with acidic $K M n O_{4}$ .
(ii) Normally, benzene gives electrophilic substitution reaction rather than electrophilic addition reaction although it has double bond.