How does vapour pressure of a solvent affected by adding a non-volatile solute to it?

The lowering of vapour pressure of a solvent by the addition of a non-volatile solute to it , is directly proportional to :

The vapour pressure of a solvent decreased by 10 mm. of Hg when a non-volatile solute was added to the solvent. The mole fraction of solute in solution is 0.2, what would be the mole fraction of solvent if decrease in vapour pressure is 20 mm of Hg:

Explain why freezing point of a solvent is lowered by adding a non-volatile solute into it.

Vapour pressure of a solution containing non-volatie solute is:

How does vapour pressure vary with temperature?