Reactivity of with the following `G.R` in the decreasing order is :
(i) `MeMgBr`
(ii) `EtMgBr`
(iii) `Me_2 CH-MgBr`
(iv) `Me_3 C - MgBr`.

Options

A. `(i) gt (ii) gt (iii) gt (iv)`
B. `(iv) gt (iii) gt (ii) gt (i)`
C. `(i) gt (ii) gt (iv) gt (iii)`
D. `(iv) gt (ii) gt (iii) gt (i)`

Answer

A

Explanation

(a) Since the `G.R` reacts by `SN^2` mechanism, the reactivity order of `SN^2` reaction is `1^@ RMgX gt 2^@ RMgX gt 3^@ RMgX`. Hence, the answer is `(a)`.