Sn1 reactions- role of the solvent?

Question

"The solvent plays an important role in both

SN1 and SN2 reactions.

SN1: better solvation of the TS lowers its

energy and increases the rate. The higher the

solvent dielectric constant the better!"

Can someone explain this? I would have thought that if solvation lowered the energy of the transition state (TS) it would decrease the rate. Or does it mean that solvation lowers the activation energy needed to get the reaction going?

Answer 1

the lower in energy the transition state is in, the easier it is going to be to get there and make the reaction go forward more rapidly