Question

What factors determine whether an alkyl halide will undergo an SN1 or an SN2 reaction?

Answer 1

Stearic hindrance, hyperconjugation, hybridization, nature of solvent used, nature of sustrate(1' 2' or 3') ' stands for degree here

Explanation:

1-more stearic hindrance, more chance to give SN1 Rn. vice versa
2-more hyperconjugation capability of a substrate, more stable will be the carbocation ultimately more chance to give SN1 Rn. vice versa
3-sp3 hybridization only give SN1 Rn.
4-polar protic solvents favour the SN1 while polar aprotic solvents favours the SN2 Rn. Since the product of the solvent may interact with carbocation intermediate and result in undesired product.
5-1' always follow SN2, while 2' may either follow any, 3' strictly follow SN1.