The Henry's law constant $(K_H)$ values of three gases $(A, B, C)$ in water are $145$,$2 \times 10^{-5}$,and $35$ kbar,respectively. The solubility of these gases in water follow the order:

Assertion : When a salt such as $NaCl$ dissolves,the $Na^{+}$ and $Cl^{-}$ ions leaving the crystal lattice acquire far greater freedom.
Reason : In thermodynamic terms,the formation of solution occurs with a favourable change in free energy,i.e.,$\Delta H$ has a high positive value and $T\Delta S$ a low negative value.

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

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

Identify from the following salts the one whose solubility in water decreases with an increase in temperature.

If four gases $A$,$B$,$C$ and $D$ have Henry's constant $(K_H)$ values $1.9 \times 10^1 \ bar$,$6.5 \times 10^{-4} \ bar$,$7.8 \times 10^{-4} \ bar$ and $6.0 \times 10^3 \ bar$ respectively,then which of the following gas has maximum solubility at the same partial pressure?