Solubility of which among the following solids in water changes slightly with temperature?

Which of the following is a solution in which the physical states of solute and solvent are liquid and solid respectively?

If the solubility of $H_2S$ in water at $STP$ is $0.195 \, m$,what is the value of $K_H$ in $bar$?

The solubility of a gas in a liquid is directly proportional to the pressure of the gas over the solution. Identify the law for this statement.

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

Henry's law constant for $CO_{2}$ in water is $1.67 \times 10^{8} \ Pa$ at $298 \ K$. Calculate the quantity of $CO_{2}$ in $500 \ mL$ of soda water when packed under $2.5 \ atm$ $CO_{2}$ pressure at $298 \ K$.