tert-Butyl chloride undergoes solvolysis in both acetic acid and formic acid. Solvolysis occurs 5000 times faster in one of these two solvents than in

the other. In which solvent is solvolysis faster? Explain your answer. (Hint: Formic acid is more polar than acetic acid.)

Solvolysis of a reaction means breaking a molecule into another form using the solvent. It is a reaction where the solvent is water or alcohol.

A general mechanism to SN1 reaction is given below,

The increase in the polarity in solvent increases the charge separation in a molecule. The above reaction proceeds through SN1 mechanism where the formation of stable cation is the rate determining step. The more stable is the cation, the more will be the rate of the reaction. Increases to polarity increases charge separation which stabilises the carbocation more. Thus, increasing the polarity of solvent increases the solvolysis reaction.

As here formic acid has more polarity than acetic acid, it increases the solvolysis reaction more.