Question

Addition of which solute in 1.0 molar KI solution will not cause a change in vapour pressure:

• A. $I_2$
• B. water
• C. $Hg{I}_2$
• D. addition of $N{a}_{2}S{O}_4$

Answer 1

Answer: (A)

$I_2$

Addition of $I_2$ in 1.0 molar KI solution will not cause a change in vapour pressure.
No. of particles does not change in case of $I_2$
$KI+I_2\to K{I}_3$
$KI+N{a}_{2}S{O}_4\to$ Increase in no. of ion
$2KI+Hg{I}_2\to K_{2}Hg{I}_4$ (decrease in no. of ion)
Addition of water changes concentration of the solution.