What is the solubility of a gas in water at $25^{\circ} C$ if the partial pressure is $0.18 \ atm$? $(K_{H} = 0.16 \ mol \ dm^{-3} \ atm^{-1})$

Assertion $(A)$: For an endothermic dissolution process,an increase in temperature increases the solubility in a nearly saturated solution.
Reason $(R)$: In a saturated solution,dynamic equilibrium exists between the dissolved solute and the undissolved solute.

The relation between the solubility of a gas in a liquid at a constant temperature and external pressure is stated by which law?

Which of the following statements is $NOT$ true about solubility?

Why is a mixture of $He-O_2$ used by deep-sea divers instead of a $N_2-O_2$ mixture?

At $T \ (K)$ the molarity of $CO_2$ (in $mol \ L^{-1}$) in $200 \ mL$ of soda water packed under a pressure of $3.4 \ bar$ is ($K_H$ of $CO_2$ in water is $1.7 \times 10^3 \ bar$ at $T \ (K)$).