Question

why ngp reactions are first order reaction?

Answer 1

Answer:

SN2 reaction that happens after an internal nucleophilic group attacks(which is known as NGP) would be more stable. In fact, the nucleophilic group that attacks is often a strong nucleophile that is quite reactive (more than the leaving group which is usually a weak base) which would only destabilise the transition state when the external nucleophile does attack.