tert-Butylbromide reacts with aq.NaOH by `S_(N)1` mechanism while n-butylbromide reacts by `S_(N)2` mechanism. Why?

Explanation

Reaction by `S_(N)1` Mechanism is favoured by the ability of the substrate to form stable carbocation intermediate.Since tert-butyl bromide is capable of forming a stable carbocation,, therefore, it reacts with NaOH by `S_(N)1`mechanism. On the other hand , reaction by `S_(N)2` mechanism is favoured in the absence of steric hindrance around ,, of the substrate. Thus,n -butyl bromine (a primary alkyl halide)reacts with NaOH by `S_(N)2` mechanism.