Explanation:
The critical temperature refers to the temperature above which a substance cannot exist in the liquid state, regardless of the pressure applied. The critical temperature of water is 374°C, while that of O2 is -118°C.

The critical temperature of a substance is dependent on the intermolecular forces of attraction between its molecules. In the case of water and O2, the difference in critical temperature can be attributed to the fact that water molecules have a dipole moment, while O2 molecules do not.

Dipole moment:
• A dipole moment is a measure of the separation of positive and negative charges in a molecule. In other words, it is a measure of the polarity of a molecule.
• The dipole moment of a water molecule arises because of the unequal sharing of electrons between the oxygen and hydrogen atoms.
• Oxygen is more electronegative than hydrogen, which means that it attracts electrons more strongly. As a result, the electrons spend more time around the oxygen atom, leading to a partial negative charge on the oxygen atom and a partial positive charge on the hydrogen atoms.

Effect of dipole moment on critical temperature:
• The presence of a dipole moment in a molecule leads to stronger intermolecular forces of attraction between its molecules.
• In the case of water, the dipole-dipole interactions between its molecules are stronger than the London dispersion forces between O2 molecules.
• This leads to a higher critical temperature for water than for O2.

Therefore, the correct answer is option 'D,' which states that the critical temperature of water is higher than that of O2 because the H2O molecule has a dipole moment.