Question

how does a solute affect the boiling point of solvent?

Answer 1

...by changing the boiling point of the solvent.

Answer 2

...If the solvent is pure, the boiling point will be known and does not vary, but when a different compound is added, it is viewed as as 'impurity' with its own unique boiling point. This alters and boiling point of the original solute, to the boiling point of the new solution.

Answer 3

Pardon my grammatical errors :)

Answer 4

and even due to change in the density