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

Assertion : Iodine is more soluble in water than in carbon tetrachloride.
Reason : Iodine is a polar compound.

In which solution,the solubility of the solute decreases with an increase in temperature?

Based on solute-solvent interactions,arrange the following in order of increasing solubility in $n$-octane and explain: Cyclohexane,$KCl$,$CH_3OH$,$CH_3CN$.

Which of the following laws represents the quantitative relationship between the solubility of gas in liquid and its pressure?

If the solubility of $NaCl$ at $20\,^{\circ}C$ is $35\,g$ per $100\,g$ of water,then on adding $50\,g$ of $NaCl$ to the same amount of water at the same temperature,the amount of salt that remains undissolved is .......... $g$.