Question

Which of the following statements is correct about a carbonyl group?

• A. The carbonyl carbon is $\text{s}\text{p}$ -hybridised
• B. The carbonyl carbon is $\text{s}\text{p}^{3}$ -hybridised
• C. The three groups attached to the carbonyl carbon lie in the same plane
• D. The three groups attached to the carbonyl carbon lie in different planes

Answer 1

Answer: (C)

In the carbonyl group, carbon atom is in a state of $\text{s}\text{p}^{2}$ hybridisation. One $\text{s}\text{p}^{2}$ hybrid orbital overlap with a unhydridised $\text{p}$ -orbital of oxygen to form $\text{C}-\text{O}$ $\text{σ}$ -bonds. The remaining two $\text{s}\text{p}^{2}$ orbitals of carbon form $\text{σ}$ -bonds with $\text{s}$ -orbitals of hydrogen or $\text{s}\text{p}^{3}$ -orbitals of carbon of the alkyl groups. The $\text{C}-\text{O}$ $\text{\pi }$ -bond is formed by the sideways overlap of $\text{p}$ -orbitals of carbon and oxygen. Thus, the three $\text{σ}$ -bonds of carbonyl carbon lie in one plane and are $120^\circ $ aprat