Question

Strongest nucleophile is:

• A. $RN{{H}_{2}}$
• B. $ROH$
• C. $C_{6}H_{5}O^{-}$
• D. $CH_{3}O^{-}$

Answer 1

Answer: (D)

$CH_{3}O^{-}$

Answer 2

Nucleophile is electron rich or negatively charged species. $R \overset{\bullet \,\bullet}{ N } H _{2}$ and $\underset{\overset{\bullet \,\bullet}{}}{\overset{\underset{\bullet \,\bullet}{}}{O}} H$ are weaker nucleophile because they don't have negative charge. The strength of $C _{6} H _{5} O ^{-}$, decreases due to presence of benzyl group which withdraws electrons from oxygen due to $-I$ effect. $CH _{3} O ^{-}$is strongest nucleophile because methyl group increases the electron density on oxygen, since it shows $+I$ effect.