Consider a solution of $CO_{2(g)}$ dissolved in water in a closed container. Which one of the following plots correctly represents the variation of $log$ (partial pressure of $CO_2$ in vapour phase above water) [y-axis] with $log$ (mole fraction of $CO_2$ in water) [x-axis] at $25^{\circ}C$?

The Henry's law constant for the dissolution of a gas in an aqueous medium is $3 \times 10^2 \ atm$. At what partial pressure of the gas will the molality of the gas in the aqueous solution be $\frac{5}{9} \ m$?

Rank the following solvents in decreasing order of their ability to dissolve the given solute (naphthalene).

Assertion: $A$ mixture of $He$ and $O_2$ is used for respiration for deep sea divers.
Reason: $He$ is soluble in blood.

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: Helium is used to dilute oxygen in diving apparatus.
Reason $R$: Helium has high solubility in $O_2$.
In the light of the above statements,choose the correct answer from the options given below:

Explain the hydration of sodium chloride.