Question

Which of the following statements is correct in the context of the allene molecule $C_3{H}_4$ ?

• A. The central carbon is $sp$-hybridized.
• B. The terminal carbon atoms are $s{p}^2$-hybridized.
• C. The planes containing the $C{H}_2$ groups are mutually perpendicular to permit the formation of two separate $\pi$-bonds.
• D. Central atom is $s{p}^2$-hybridized.

Answer 1

Answer: (A), (B), (C)

The terminal carbon atoms are $s{p}^2$-hybridized.
The planes containing the $C{H}_2$ groups are mutually perpendicular to permit the formation of two separate $\pi$-bonds.
The central carbon is $sp$-hybridized.

In the allene molecule, the central $C$ atom is $sp$ hybridized and other two $C$ atoms are $s{p}^2$ hybridized.
Thus, the central $C$ atom has two double bonds whereas other two $C$ atoms have on double bond each.
There are two unhybridized p orbitals present on the central carbon atom which are mutually perpendicular. These two unhybridized p orbitals are used to form two pi bonds with two adjacent $C$ atoms.
Hence, the planes containing the $C{H}_2$ groups are mutually perpendicular.
Thus, the statements A, B and C are correct.