Question

The cylindrical shape of an alkyne is due to

• A. three sigma C-C bonds
• B. three $π$C-C bonds
• C. two sigma C-C and one $π$ C-C bonds
• D. one sigma C-C and two $π$ C-C bonds

Answer 1

Answer: (D)

one sigma C-C and two $π$ C-C bonds

Answer 2

The correct answer is D:one sigma $C-C$ and two $C-C$ bonds
In alkynes $C \equiv C$ is present, in such bond one sigma and two $π$-bonds are present. Sigma bond is formed by sp-hybrid orbitals whereas $π$-bonds are formed by unhybridised orbitals. Hence, it shows cylindrical shape.