Why does water have an unusually low vapor pressure for a liquid? the oxygen-hydrogen bond in a water molecule is unusually strong, which decreases the rate of evaporation. the oxygen-hydrogen bond in a water molecule is unusually weak, which increases the rate of evaporation. hydrogen bonding repels water molecules at the surface, increasing the rate of evaporation. hydrogen bonding attracts water molecules to one another and slows the rate of evaporation.

Option (a) is the correct answer.

Explanation:

Vapor pressure is defined as the pressure exerted by vapors or gas on the surface of a liquid.

So, the greater the intermolecular forces present between the molecules of a substance, lower the vapor pressure.

Evaporation is defined as the ability of a substance's molecules to readily convert into vapors.

In water molecules, there exists hydrogen bonding which is a strong bonding. As a result, molecules are not able to readily convert into vapors due to which no force will exert easily on the surface of water molecules.

Hence, water will have an unusually low vapor pressure.

Thus, we can conclude that water have an unusually low vapor pressure for a liquid because the oxygen-hydrogen bond in a water molecule is unusually strong, which decreases the rate of evaporation.