Chapter 12, Problem 84A

Interpretation Introduction

Interpretation:

Intermolecular forces must be used to explain that oxygen is a gas but water is a liquid.

Concept introduction:

Physical states of substances depend on the intermolecular force present.

Answer to Problem 84A

Oxygen has weak dispersion force but water has hydrogen bonds. So oxygen is gas and water is liquid.

Explanation of Solution

Stronger is the intermolecular force closer is the molecules. It means intermolecular distance is less. Oxygen is a non-polar molecule. It can have induced dipole moment which is temporary. This induced dipole force is dispersion force which is weaker as compared to hydrogen bonds in water. So water molecules are associated and these have stronger intermolecular force as compared to oxygen.

This water is a liquid but oxygen is a gas.

Conclusion

Due to hydrogen bonding in water it is liquid unlike oxygen with dispersion force.