Question

Effect of adding a non-volatile solute to a solvent is :

• A. to lower the vapour pressure
• B. to increase its freezing point
• C. to increase its boiling point
• D. to decrease its osmotic pressure

Answer 1

Answer: (A), (C)

The correct options are
A to lower the vapour pressure
C to increase its boiling point

When ever if a non volatile solution is added to a pure solvent it increases its boiling point due to increase in molecular attractions due to the non volatile solute with the solvent.Increase in boiling point is a colloidal property. When ever if a non volatile solution is added to a pure solvent it decreases its vapour pressure due to increase in molecular attractions due to the non volatile solute with the solvent.Lowering of vapour pressure is a colloidal property. So, lowering of vapour pressure and increase in boiling point takes place if a non volatile solute is added to solvent.

Hence option $A,C$ are correct.