What is the process called when a liquid turns to gas?

The process of a liquid turning into a gas is known as evaporation. Evaporation occurs when molecules at the surface of a liquid gain enough energy to overcome the intermolecular forces binding them together, allowing them to escape into the air as vapor. This process can take place at any temperature and occurs as long as there is a vapor pressure above the liquid.

In contrast, boiling refers to a rapid transition from liquid to gas that occurs at a specific temperature known as the boiling point, where the vapor pressure of the liquid equals the atmospheric pressure. Condensation is the process by which gas turns into a liquid, and freezing refers to the transition from liquid to solid. Thus, evaporation is specifically the slow conversion of a liquid to a gas, which is why it is the correct answer in this context.