When a nonvolatile solute is added to a solvent, it tends to the freezing point and the boiling point, compared to the pure solvent.

decreases and increases

Explanation:

the addition of solutes can alter the freezing point and the boiling point .the changes in solute content where there is an addition of solutes results in the dropping of freezing point and increase in boiling point.this is known as freezing point depression and boiling point depression.