Question

Find out the order of stability between $\left(A\right)C{H}_3-C{H}_2-\underset{\underset{COOH}{|}}{C}H-\stackrel{-}{C}H-C{H}_3$
$\left(B\right)C{H}_3-\underset{\underset{COOH}{|}}{C}H-C{H}_2-\stackrel{-}{C}H-C{H}_3$
$\left(C\right)\underset{\underset{COOH}{|}}{C}{H}_2-C{H}_2-C{H}_2-\stackrel{-}{C}H-C{H}_3$

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

Answer 1

The correct option is A A>B>C

$-COOH$ is an electron withdrawing group. Therefore, it will increase the stability of the carbanion by withdrawing electron and decreasing electron density on carbanion.
As the distance between the electron withdrawing group $(-COOH)$ and carbanion carbon increases,the -I effect of $(-COOH)$ group decreases as -I effect is distance dependent and vanishes after 2nd carbon.
Therefore, the order of stability of carbanion is:
A>B>C