If a substance '$$A$$' dissolves in solution of a mixture of '$$B$$' and '$$C$$' with their respective number of moles as $$\mathrm{n}_{\mathrm{A}}, \mathrm{n}_{\mathrm{B}}$$ and $$\mathrm{n}_{\mathrm{C}_3}$$. Mole fraction of $$\mathrm{C}$$ in the solution is

The quantity which changes with temperature is :

A metal chloride contains $$55.0 \%$$ of chlorine by weight . $$100 \mathrm{~mL}$$ vapours of the metal chloride at STP weigh $$0.57 \mathrm{~g}$$. The molecular formula of the metal chloride is

(Given: Atomic mass of chlorine is $$35.5 \mathrm{u}$$)

A solution is prepared by adding $$2 \mathrm{~g}$$ of "$$\mathrm{X}$$" to 1 mole of water. Mass percent of "$$\mathrm{X}$$" in the solution is :