Final answer:
Methanol is the solvent that would react the fastest to turn (s)-2-chloropentane and hydroxide into (r)-2-pentanol.
Step-by-step explanation:
The solvent that would react the fastest to turn (s)-2-chloropentane and hydroxide into (r)-2-pentanol is methanol. Methanol is a polar protic solvent that can act as a nucleophile. It reacts faster than water, ammonia, and acetonitrile. Methanol's ability to donate a hydrogen ion (proton) and act as a nucleophile allows it to facilitate the conversion of (s)-2-chloropentane to (r)-2-pentanol.