How do solutes affect the boiling point?

Solutes raise the boiling point of a solution.

When a is added to a solution, the solutes create the addition of that interact with the in such a way that more energy is required to evaporate the solvent.

Let's use salt water for example. Na+ and Cl- atoms are constantly forming bonds with each other and then separating, which interact with ##H_2O## molecules in the form of hydrogen . Thus, when the water molecules are trying to be boiled/evaporated, the Na+ and Cl- atoms are bonding with or bumping into the ##H_2O## molecules, which requires additional energy to separate.

Similarly, solutes affect the freezing point of a solution. For example, ethylene glycol is mixed with water to form antifreeze, which boils at a higher temperature than water alone and also freezes at a lower temperature. This is why you don't add only water to the radiator in your vehicle's cooling system, but must mix it with ethylene glycol (otherwise, your engine block would crack if the internal temperature of the engine exceeded 212 degrees F or temperatures reached below 32 degrees F.

Depending on the outside temperature, the ratio of of ethylene glycol to water is changed to provide you with the appropriate amount of protection. For example, in the southern United States, where is seldom gets much below freezing in the winter, a 30/70% ratio of ethylene glycol is appropriate; however, in Canada where it is much colder, you may require a 40/60% ratio.