primary alkyl halide undergo nucleophilic substitution through SN2 mechanism while tertiary through SN1. why?

primary alkyl halide undergo nucleophilic substitution through SN2 mec

1.	primary alkyl halide undergo nucleophilic substitution through SN2 mechanism while tertiary through SN1. why?
Answer» SN1 is a SLOW reaction which OCCURS with formation of an intermediate and in turn depends on stability of intermediate. TERTIARY carbocation is more stable than 1 degree carbon. SN2 depends on AMOUNT of +ve CHARGE on position of nucleophile attack. So primary undergo SN2