Question

Hybridisation of the negative carbons in (1) and (2) are:

• A. sp2 and sp3
• B. sp3 and sp2
• C. both sp2
• D. both sp3

Answer 1

The Correct Option is A

The correct answer is sp² and sp³.

Here's why:

• Hybridization and Carbanions: A carbanion is a carbon atom with a negative charge and three substituents. The hybridization depends on whether the lone pair on the carbon is involved in resonance.
• Structure (1): In structure (1), the carbanion is directly attached to a carbonyl group. The negative charge can delocalize into the carbonyl group through resonance: $^-C - C=O <-> C = C - O^-$ This resonance delocalization makes the carbanion sp² hybridized. The carbon has 3 sigma bonds and 0 lone pair. The lone pair participates in pi-bonding.
• Structure (2): In structure (2), the carbanion is attached to 3 other atoms with single bonds. Therefore, it is sp³ hybridized. The carbon has 3 sigma bonds and 1 lone pair.

Therefore, the hybridization of the negatively charged carbons in (1) and (2) are sp² and sp³, respectively.

Correct Answer: sp² and sp³