The $$K_{\mathrm{H}}$$ value ($$\mathrm{K}$$ bar) of argon (I), carbondioxide (II), formaldehyde (III) and methane (IV) are respectively $$40.3,167, 1.83 \times 0^{-5}$$ and 0.413 at $$298 \mathrm{~K}$$. The increasing order of solubility of gas in liquid is

The vapour pressure of pure liquids $$A$$ and $$B$$ are 450 and $$700 \mathrm{~mm}$$ of $$\mathrm{Hg}$$ at $$350 \mathrm{~K}$$ respectively. If the total vapour pressure of the mixture is $$600 \mathrm{~mm}$$ of $$\mathrm{Hg}$$, the composition of the mixture in the solution is

Which of the following pair of solutions is isotonic?

Solute '$$X$$' dimerises in water to the extent of $$80\%$$. 2.5g of '$$X$$' in $$100 \mathrm{~g}$$ of water increases the boiling point by $$0.3^{\circ} \mathrm{C}$$. The molar mass of 'X' is $$[K_b=0.52 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}]$$