Question

Among the following molecules, the molecule with linear shape is:

• A. Water
• B. ${\mathrm{BH}}_3$
• C. ${\mathrm{CH}}_4$
• D. ${\mathrm{CO}}_2$

Answer 1

The correct option is D

${\mathrm{CO}}_2$

Explanation for correct option:

D. ${\mathrm{CO}}_2$

Hybridization:

• “Hybridization is defined as the process of intermixing of the orbitals of slightly different energies so as to redistribute their energies, resulting in the formation of a new set of orbitals of equivalent energies and shape.”

Hybridization of carbon in carbon dioxide:

• The hybridization state of carbon in ${\mathrm{CO}}_2$ is $\mathrm{sp}$ hybridized.
• The two sp hybridized orbitals of the carbon atom overlap with two p orbitals of the oxygen atom to form two sigma $\mathrm{\sigma }$ bonds while the other two electrons of carbon are involved in $\mathrm{\pi }-\mathrm{\pi }$ bonding with the oxygen atom.
• Carbon dioxide has a linear geometry.

Explanation for incorrect options:

A. Water has a bent geometry. In hybridization of ${\mathrm{H}}_2\mathrm{O}$, the oxygen atom is ${\mathrm{sp}}^3$ hybridized.

B. In ${\mathrm{BH}}_3$, Boron has three valence electrons, it will have ${\mathrm{sp}}^2$ hybridization. As per VSEPR theory, it has trigonal planar geometry.

C. In ${\mathrm{CH}}_4$, the hybridization ${\mathrm{sp}}^3$ and has tetrahedral geometry as per VSEPR theory.

Hence, the correct option is D i.e. ${\mathrm{CO}}_2$.