Question

Identify the nucleophilicity order in the following $H{O}^{\ominus }$ ${CH}_{3}CO{O}^{\ominus }$ in protic solvent:

Answer 1

$C{H}_{3}CO{O}^{-}$ is more nucleophilic than $O{H}^{-}$.

In a protic solvent, an ion like $O{H}^{-}$ is surrounded by a tight shell of solvent molecules. This hinders its ability to attack the substrate, so its nucleophilicity decreases. A highly electronegative atom is a poor nucleophile because it is unwilling to share its electrons.

The charge density on each oxygen atom is decreased, so acetate ion is not a strong nucleophile.