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

To avoid bends sickness,the tanks used by scuba divers are filled with air and diluted with ......

The $K_H$ values (in $k\text{bar}$) of argon $(I)$,carbon dioxide $(II)$,formaldehyde $(III)$,and methane $(IV)$ are $40.3$,$1.67$,$1.83 \times 10^{-5}$,and $0.413$ respectively at $298 \ K$. The increasing order of solubility of these gases in liquid is:

Which one of the following is least soluble in Acetone?

State Henry's law and mention some important applications.

Which of the following statement$(s)$ is/are correct regarding the solubility of solid $I_2$?