The vapour pressure of the solution of two liquids $\mathrm{A} \left({\mathrm{P}}^{\circ }=80 \mathrm{mm}\right)$ and $\mathrm{B} \left({\mathrm{P}}^{\circ }=120 \mathrm{mm}\right)$ is found to be $100 \mathrm{mm}$, when ${\mathrm{X}}_{\mathrm{A}}=0.4$. The result shows that

When $\mathrm{KCl}$ dissolves in water (assume endothermic dissolution), then:

The volume of water that must be added to a mixture of $250 \mathrm{ml}$ of $0.6 \mathrm{M} \mathrm{HCl}$ and $750\mathrm{ml}$ of $0.2 \mathrm{M} \mathrm{HCl}$ to obtain $0.25\mathrm{M}$ solution of $\mathrm{HCl}$ is: