The statement "The mass of a gas dissolved in a given mass of a solvent at any temperature is proportional to the pressure of the gas above the solvent" is

Why is a soda water bottle kept in a cold place?

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

How many millimoles of nitrogen dissolve when nitrogen is passed in $1 \ L$ water at $293 \ K$ temperature? $[$ The value of $K_H$ is $7.648 \times 10^4 \ bar$ and partial pressure of $N_2$ gas is $0.987 \ bar.]$

Choose the correct statement.

The solubility of $N_2$ gas in water at $25 \text{ }^\circ\text{C}$ and $1 \text{ bar}$ is $6.85 \times 10^{-4} \text{ mol L}^{-1}$. Calculate the solubility of $N_2$ gas in water at the same temperature when the partial pressure of $N_2$ is $0.70 \text{ bar}$.