Does the solvent play a role in determining which pathway the reaction will take, SN1 versus SN2? How?

1 Answer
Oct 19, 2015


It affects more their reaction rates.


The solvents plays a minimal role in determining the mechanism as #S_(N1) or S_(N2)#.

#S_(N1)# mechanism favours polar protic solvents however, #S_(N2)# mechanism favours polar aprotic solvents.

Polar protic solvents can hydrogen bond (or form a strong intermolecular ion-dipole interaction) with the nucleophile and therefore, weakening its nucleophilicity, however, polar aprotic solvents do not interact with the nucleophile.

This is because, #S_(N1)# mechanism favours weak nucleophile and #S_(N2)# mechanism favours strong nucleophile.

Here is a video that explains in details how to predict the mechanism as #S_(N1) or S_(N2)#.