A general mechanism for aromatic electrophilic substitution reaction is. (K_(1) and K_(2) are rate constant for the forward reaction) also C-D bond in harder to break than a C-H bond, and consequently reaction in which C-D bond broken proceed more slowly than the reaction in which C-H bond are broken. However experimetns reveal that nitration of C_(6)H_(6) and C_(6)D_(6) proceeds at equal rates while the same is not true for sulphonation of C_(6)H_(6) and C_(6)D_(6). Q. What can be inferred regarding mechanism of sulphonation of C_(6)H_(6) and C_(6)D_(6)

A general mechanism for aromatic electrophilic substitution reaction

1.	A general mechanism for aromatic electrophilic substitution reaction is. (K_(1) and K_(2) are rate constant for the forward reaction) also C-D bond in harder to break than a C-H bond, and consequently reaction in which C-D bond broken proceed more slowly than the reaction in which C-H bond are broken. However experimetns reveal that nitration of C_(6)H_(6) and C_(6)D_(6) proceeds at equal rates while the same is not true for sulphonation of C_(6)H_(6) and C_(6)D_(6). Q. What can be inferred regarding mechanism of sulphonation of C_(6)H_(6) and C_(6)D_(6)
Answer» Activation energy for the first step in `C_(6)H_(6)` is GREATER than that of `C_(6)D_(6)` Activation energy for the first step in `C_(6)H_(6)` is smaller than that of `C_(6)D_(6)` When benzene is sulphonated, Ea (i) and Ea (II) are closer than they are when `C_(6)D_(6)` is sulphonated. When `C_(6)D_(6)` is sulphonated Ea (i) and Ea (ii) COMES very close and `K_(2)` approaches `K_(1)`. Solution :`r_(1) cong r_(2)`.