Question

What are the shapes of ethyne and methane?

• A. Square planar and linear
• B. Tetrahedral and trigonal planar
• C. Linear and tetrahedral
• D. Trigonal planar and linear

Answer 1

Answer: (C)

Ethyne $\left(C_2{H}_2\right)$

Number of $\sigma$ -bonds at $C$ -atom $=2$

Number of lone pair of electrons at $C$ -atom $=0$

$\therefore$ Total $=2+0=2$

$\therefore$ Hybridisation is $sp$.

$\therefore C_2{H}_2$ is linear

Methane $\left(C{H}_4\right)$

Number of $\sigma$ bonds at $C$ -atom $=4$

Number of-lone pair of electrons at $C$ -atom $=0$

$\therefore$ Total $=4+0=4$

$\therefore$ Hybridisation is $s{p}^3$.

$\therefore C{H}_4$ is tetrahedral.