Question

Which statement explains why low temperature and high pressure are required to liquefy chlorine gas?

Answer 1

Answer: (3) Chlorine molecules have weak intermolecular forces of attraction.

Explanation: In order to liquefy a gas, the molecules must be brought closer. Chlorine being a gas has weak inter molecular forces of attraction and the molecules are far away from each other.

Thus decreasing the temperature would decrease the kinetic energy of the molecules and increase in pressure would bring the molecules close together to convert it into  liquid phase.

Answer 2

4 is correct. Since gases are made of rapidly moving molecules with a relatively high amount of kinetic energy, the molecules have a hard time coming together to form a liquid. You must lower their kinetic energy with a low temperature and force the molecules together with high pressure.