The solubility of a gas in a liquid is directly proportional to the partial pressure of the gas. This statement is known as ...

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:

Calculate the pressure of the gas if the solubility of the gas in water at $25^{\circ} C$ is $6.85 \times 10^{-4} \ mol \ dm^{-3}$. (Henry's law constant $K_H$ is $6.85 \times 10^{-4} \ mol \ dm^{-3} \ bar^{-1}$) (in $bar$)

Calculate the quantity of $CO_2$ required to prepare $1 \,L$ of soda water when the soda water is packed under $2 \,atm$ of $CO_2$. [Henry's law constant for $CO_2$ is $1.67 \times 10^8 \,Pa$] (in $\,g$)

What happens when a saturated solution of sugar is heated?

$(a)$ Explain the following phenomena with the help of Henry’s law.
$(i)$ Painful condition known as bends.
$(ii)$ Feeling of weakness and discomfort in breathing at high altitude.
$(b)$ Why does a soda water bottle kept at room temperature fizz on opening?