Which among the following is NOT colligative property?

What is the molality of solution of a non-volatile solute having boiling point elevation $$7.15 \mathrm{~K}$$ and molal elevation constant $$2.75 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}$$ ?

Which among the following salts exhibits inverse relation between it's solubility and temperature?

A closed container contains mixture of non-reacting gases $$A$$ and $$B$$. Partial pressure of $$A$$ and $$B$$ are 4.5 bar and 5.5 bar respectively. Find mole fractions of $$A$$ and $$B$$ respectively?