Alcohol and water have different melting points. which method would you use to separate them?

The process of separating alcohol from water can be done in several different ways. The most familiar method is through heating the blended liquid. Since alcohol has a lower boiling temperature than water, it will rapidly become steam. It can then be condensed into a separate container. You can also freeze the alcoholic mixture, which allows for partial removal of the nonalcoholic components; what remains will be more rich in alcohol. Use ordinary table salt to separate isopropyl alcohol from water. The result will be a condensed isopropyl alcohol, not a drinking alcohol.

It will be less because some of the mass would be converted into energy.