Although both `CO_(2)` and `H_(2)O` are triatomic molecules, the shape of `H_(2)O` molecules in bent while that of `CO_(2)` is linear. Explain this on the basis of dipole moment.

Explanation

Carbon dioxide is a linear molecule in which two C=O bonds are oriented the opposite directins at an angel of `180^(@).` The dipole moment of C=O bond is 2.3D but due to linear structure of `CO_(2)` the bond diploes of two C=O bonds cancel with each other. Therefore, the resultant dipole moment of the molecule is zero. On the other hand, `H_(2)O` is a polar molecule having dipole moment 1.84 D. Actually `H_(2)O` molecule has a bent structure in which the O-H bonds are oriented at an angle of `104.5^(@)`and do not cancel the bond dipole moments of each other. The molecular dipole moment of `H_(2)O` (`mu` = 1.84 D) is the resultant of the individual values of the bond dipole moment of two O-H bonds.