Solvent effects on SN1 reactivity

In contrast to the SN2 mechanism (Section 2.4.3), the structure of the transition state of the rate-determining step in the SN1 mechanism cannot be depicted in a simple way. As an aid, we 

50% S-Enantiomer + 50% A -Enantiomer, thus 0% S-Enantiomer + 100% racemic mixture 

It is important to note that just because a reaction occurs with an species that could give rise to a reasonably stable cation and the solvent is polar does not mean that an SN1 reaction is necessarily taking place. 

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