question_answer 19)

Although both \[C{{O}_{2}}\] and \[{{H}_{2}}O\] are triatomic molecules, the shape of \[{{H}_{2}}O\] molecule is bent while that of \[C{{O}_{2}}\] is linear. Explain this on the basis of dipole moment.

Answer:

Net dipole moment of \[C{{O}_{2}}\] molecule is zero inspite of the fact that CO bond is polar. This can be only possible if \[C{{O}_{2}}\] is linear so that dipole moments of CO, which are equal and opposite, cancel each other. \[\underset{Linear\,molecule}{\mathop{O=C=O}}\,\] On the other hand, water molecule is found to possess a dipole moment of 1.84 D. This shows it has a bent structure.