water and alcohol have different boiling point; you heat them untill the boiling point of the alcohol( the boiling point of alcohol is lower than water) so that you can collect the evaporated alcohol and left behind the water.
Adding a solute to a mixture does not change its boiling point, but it will change its boiling range. By adding rubbing alcohol, which has a lower boiling point than water, it will depress the boiling range of the solution.
Liquid alcohol will change to vapor when its temperature reaches its boiling temperature. When alcohol reaches its boiling temperature, each molecule of alcohol has enough energy to separate from each other, so each molecule can move freely. The boiling point of liquid alcohol is 351K or 78C
Alcohol is a class of chemicals, not a single chemical. Each one has a different boiling point. The alcohol that people drink is ethyl alcohol, or ethanol. The boiling point of ethyl alcohol is 78oC. Since we add 273 into the the number while changing it to Kelvin Therefore, 78+273 = 351 in Kelvin.