A mixture of 3.0 moles of $\mathrm{Na}_2 \mathrm{O}$ and 1.5 mol of $\mathrm{KO}_2$ is dissolved in 1000 mL of water. The vapour pressure of the solution in Torr, at $100^{\circ} \mathrm{C}$ is

$15 \%$ aqueous solution of glucose (molecular weight $=180 \mathrm{~g} / \mathrm{mol}$ ) is isotonic with $8 \%$ aqueous solution containing an unknown non-dissociable solute. What is the molecular weight of the unknown solute?

The vapour pressure of pure water is 23 mmHg . The vapour pressure of an aqueous solution, which contains 10 mass per cent of solute ' $A$ ' having molecular weight 50 is

An aqueous solution of $98 \%(w / w) \mathrm{H}_2 \mathrm{SO}_4$ has density of $1.02 \mathrm{~g} / \mathrm{cc}$. The molality of the solution is