Which of the following is an example of a solution in which the solute is a gas and the solvent is a solid?

Choose the correct statement about Henry's constant $(K_H)$.
$I$. $K_H$ increases with increase in temperature generally.
$II$. $K_H$ decreases with increase in temperature generally.
$III$. $K_H$ is the characteristic constant of the gas-solvent system.

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

If $N_2$ gas is bubbled through water at $293 \ K$,how many millimoles of $N_2$ gas would dissolve in $1 \ L$ of water? Assume that $N_2$ exerts a partial pressure of $0.987 \ bar$. Given that Henry's law constant for $N_2$ at $293 \ K$ is $76.48 \ kbar$.

$K_{H}$ values for $H_2, CO_2, CH_4$ and $O_2$ at $298 \ K$ are $71.18, 1.67, 41.85$ and $34.86 \ kbar$ respectively. Arrange these gases in the increasing order of their solubility.

Solubility curves of four ionic salts $X$,$Y$,$Z$,and $W$ are given below. In which case is the value of $\Delta H_{sol.} < 0$?