Question

The correct order of stability for the following carbanions is:
A.
B.
C.

• A. C > A > B
• B. A > C > B
• C. C > B > A
• D. B > C > A

Answer 1

The correct option is A C > A > B

$\text{Stability of carbanion}\propto -Ieffect\propto \frac{1}{+Ieffect}$

The priority order of the factors upon which the strength of inductive effect depends is:
Distance > Number > Power

Hence, the $-I$ effect of $-N{O}_2$ group will be the least and therefore, the stability of carbanion B will be the least.
Between $-Cl$ and $-CHO$ groups, the $-I$ effect of $-CHO$ is more due to the higher electron-withdrawing nature of the $-CHO$ group than $-Cl$ group.

Therefore, the correct order of stability of carbanions is C > A > B.