Vapour pressure of a pure solvent is 550 mm of Hg . By addition of a non volatile solute it decreases to 510 mm of Hg . Calculate the mole fraction of solute in solution.

Identify the false statement among the following.

Calculate the solubility of a gas having partial pressure 0.15 bar at $25^{\circ} \mathrm{C}$. $\left[\mathrm{K}_{\mathrm{H}}=0.16 \mathrm{~mol} \mathrm{dm}^{-3} \mathrm{bar}^{-1}\right]$

Which from following ionic solids exhibits decrease in its solubility in water with increase of temperature?