Question
Chemistry Question on Solutions
Addition of a non-volatile solute in a volatile ideal solvent
A
increases the vapour pressure of the solvent
B
decreases the vapour pressure of the solvent
C
decreases the boiling pomt of the solvent
D
increases the freezing point of the solvent
Answer
decreases the vapour pressure of the solvent
Explanation
Solution
Addition of a non-volatile solute in a volatile ideal solvent decreases the vapour pressure of the solvent because if a non-volatile solute is added to the solvent temperature falls (since dissolution of a solute is an endothermic process) and thus, vapour pressure of the solution is lower than that of the pure solvent.