Question

Which of the following statements Is true for carbonyl group?

Options

• The carbonyl bond is weaker as compared to double bond in alkene.

• \[\ce{C - C - O}\] bond angle is 90°.

• Carbon atom forms three sigma bonds.

• Carbon atom is sp³ hybridised.

Answer 1

Carbon atom forms three sigma bonds.

Explanation:

The carbon atom forms three sigma bonds in the carbonyl group. It can be readily demonstrated as follows:

\[\begin{array}{cc}
\ce{O}\\
||\\
\ce{C}\\
/\phantom{..}\backslash\\
\phantom{.}\ce{R1}\phantom{..}\ce{R2}\phantom{}
\end{array}\]

The carbonyl carbon atom is sp²-hybridised contributes one electron to each of three hybrid orbitals, forming three sigma (σ) bonds. The n-electron cloud is above and below the plane. The bond angles are approximately 120° as expected of a trigonal planar structure. Because of the greater electronegativity of oxygen, the carbonyl group is polar and forms a stable bond in comparison with the non-polar double bond of an alkene.