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?

Calculate molar mass of nonvolatile solute if a solution containing 0.35 g solute in 100 g water has boiling point elevation 0.01 K $\left[\mathrm{K}_{\mathrm{b}}=0.50 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}\right.$ ]

0.2 molal aqueous solution of KCl freezes at $-0.680^{\circ} \mathrm{C}$. Calculate van't Hoff factor for this solution. $\left(\mathrm{K}_{\mathrm{f}}=1.86 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}\right)$