Question

Which of the following reaction intermediate cannot show $sp^{2}$ hybridisation}

• A. Carbocation
• B. Carbanion
• C. Singlet carbene
• D. Carbon free radical

Hint:

Carbanion usually has \(sp^3\) hybridisation due to lone pair on carbon.

Answer 1

The Correct Option is B

Concept:
Reaction intermediates have characteristic hybridisation depending on electron arrangement around carbon atom.
Step 1:
Carbocation contains six electrons around carbon and has trigonal planar structure. \[ sp^{2} \] hybridisation.
Step 2:
Carbon free radical generally shows: \[ sp^{2} \] hybridisation. Singlet carbene can also show: \[ sp^{2} \] hybridisation.
Step 3:
Carbanion possesses one lone pair on carbon. It generally has pyramidal geometry with: \[ sp^{3} \] hybridisation.
Step 4:
Hence reaction intermediate that cannot show \(sp^{2}\) hybridisation is: \[ \boxed{\text{Carbanion}} \] \[ \boxed{\text{Correct Option = (2)}} \]