An endothermic reaction is one in which energy is absorbed. which of the following is an endothermic reaction in terms of latent heat?
a) liquid water changes to water vapor
b) liquid water changes to solid water
c) water vapor changes to solid water
d) water vapor changes to liquid water

A) Liquid water changes to water vapor.

Option 'A' is correct.

Explanation:

An endothermic reaction is a reaction in which large amount of energy is absorbed in the form of heat.

It may be found in two process:

1) Chemical process

2) Physical process.

Examples of endothermic reaction is melting ice etc.

that means liquid water changes to water vapor.

Hence, Option 'A' is correct.