$$x \%(w / V)$$ solution of urea is isotonic with $$4 \%$$ $$(w / V)$$ solution of a non-volatile solute of molar mass $$120 \mathrm{~g} \mathrm{~mol}^{-1}$$. The value of $$x$$ is

At $$T(\mathrm{~K}) \times \mathrm{g}$$ of a non-volatile solid (molar mass $$78 \mathrm{~g} \mathrm{~mol}^{-1}$$) when added to 0.5 kg water, lowered its freezing point by $$1.0^{\circ} \mathrm{C}$$. What is $$x$$ (in g)? ($$K_f$$ of water at $$T(\mathrm{~K})=1.86 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}$$)

Assertion (A) Blood cells collapse when suspended in saline water.

Reason (R) Cell membrane dissolves in saline water.

If the $$K_{\mathrm{H}}$$ values for $$\operatorname{Ar}(g), \mathrm{CO}_2(g), \mathrm{HCHO}(g)$$ and $$\mathrm{CH}_4(\mathrm{~g})$$ respectively are $$40.39,1.67, 1.83 \times 10^{-5}$$ and $$0.413$$ , then identify the correct increasing order of their solubilities.