Question

The decreasing order of nucleophilicity for the following anions is

$\text{CH}_{3} \text{CO}_{2}^{-} \text{,} \, \text{CH}_{\text{3}} \text{O}^{-} \text{,} \, \text{C}_{\text{6}} \text{H}_{\text{5}} \text{O}^{-} \text{,} \, \text{NO}_{\text{3}}^{-}$

• A. $CH_{3}CO_{2}^{-}>CH_{3}O^{-}>C_{6}H_{5}O^{-}>NO_{3}^{-}$
• B. $CH_{3}O^{-}>NO_{3}^{-}>C_{6}H_{5}O^{-}>CH_{3}CO_{2}^{-}$
• C. $CH_{3}O^{-}>C_{6}H_{5}O^{-}>CH_{3}CO_{2}^{-}>NO_{3}^{-}$
• D. $C_{6}H_{5}O^{-}>CH_{3}O^{-}>NO_{3}^{-}>CH_{3}CO_{2}^{-}$

Answer 1

Answer: (C)

Since the electron donating atom is same, the nucleophilicity parallels basicity.

A conjugate base of a strong acid is weak and vice-versa.

The order of acidity is

$CH_{3}OH < C_{6}H_{5}OH < CH_{3}COOH < HNO_{3}$

Thus, the order of basicity and nucleophilicity is

$CH_{3}O^{-}>C_{6}H_{5}O^{-}>CH_{3}CO_{2}^{-}>NO_{3}^{-}$