Question

How to decide when sn2 and when sn1 happens definitely?

Answer 1

$\huge\red{As-Salamualykum-}$

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Sn1 occurs in tertiary alkylhalides in polar solvent

While

Sn2 occurs in Primary alkyl halides in non polar solvent .

And ......

IN secondary alkyly halides this mechanism depends on nature of solvent .

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