Question

The order of decreasing stability of the carbanions is
$\left( CH _{3}\right)_{3} \overset{-}{C} (1),\left( CH _{3}\right)_{2} \overset{-}{C}H (2), CH _{3} \overset{-}{C} H _{2}(3), C _{6} H _{5} \overset{-}{C} H _{2}(4)$

• A. 1 > 2 > 3 > 4
• B. 4 > 3 > 2 > 1
• C. 1 > 2 > 4 > 3
• D. 4 > 1 > 2 > 3

Answer 1

Answer: (B)

The stability of the carbanion decreases with increase in number of alkyl groups. However, phenyl group stabilizes the carbanion due to resonance effect.
$\therefore $ The order of stability of given ions is as follows
$C_{6} H_{5} \bar{C} H_{2}>C H_{3} \bar{C} H_{2}>\left(C H_{3}\right)_{2} \bar{C} H>\left(C H_{3}\right)_{3} \bar{C}$ or $4>3>2>1$