Question

An aqueous solution is $1$ molal in $KI$. Which change will cause the vapour pressure of the solution to increase?

• A. Addition of $NaCl$
• B. Addition of $N{a}_{2}S{O}_4$
• C. Addition of $1$ molal $KI$
• D. Addition of water

Answer 1

The correct option is D Addition of water

Vapor pressure depends on the surface area of the solution. When we add the solvent, we dilute the solution or increase the surface area to the contrary when we add the solute to decrease the surface area. Hence, addition of water will change the vapor pressure.