Question

Both ${CO}_2$ and $H_{2}O$ contain polar covalent bonds but ${CO}_2$ is non-polar while $H_{2}O$ is polar because:

• A. H atom is smaller than C atom
• B. ${CO}_2$ is a linear molecule while $H_{2}O$ is an angular molecule
• C. O-H bond is more polar than C-H bond
• D. ${CO}_2$ contains multiple bonds while $H_{2}O$ has only single bonds

Answer 1

The correct option is B ${CO}_2$ is a linear molecule while $H_{2}O$ is an angular molecule

A polar covalent bond is an unequal sharing of electrons between two atoms with different electronegativities.

Both $C{O}_2$ and $H_{2}O$ have two polar bonds. However the dipoles in the linear $C{O}_2$ molecule cancel each other out, meaning that the $C{O}_2$ molecule is non-polar.

$H_{2}O$ is planar but bent and the bond dipoles and unshared electron dipole moments do not sum to zero.