# What makes ethanoic acid a weaker electrophile than ethanoyl chloride?

Acetyl chloride, ${H}_{3} C - C \left(= O\right) C l$, has a $C {l}^{-}$ leaving group. Acetic acid, ${H}_{3} C - C \left(= O\right) O H$, has an $H {O}^{-}$ leaving group. Of course, hydroxide is a much stronger base (and stronger nucleophile) than chloride, and the differential ease of substitution reflects this