Although both `CO_2 and H_2 O` are triatomic molecules, the shape of `H_2 O` molecule is bent while that of `CO_2` is linear. Explain this on the basis of dipole moment.

Explanation

The dipole moment show that the net dipole moment of `CO_(2)` molecule is zero. This is possible only if `CO_(2)` is a linear molecule `(O=C=O)` so that dipole moments of `C-O` are equal and opposite and hence cancel out. On the other hand, `H_(2)O` molecule is found to have a net dipole moment `(1.84 D)` though it contains two `O-H` bonds. This shows that it is a bend molecule.