Rank the following substances in order from most soluble in water to least soluble in water: ethane, C2H6; 2-butanol, C4H9OH; potassium chloride, KCl; and propane, C3H8.

Potassium chloride > Butanol >Propane > Ethane

Explanation:

Water is a polar solvent and it is likely to dissolve polar molecules.

KCl is ionic in nature and is completely polar and the solubility of the salt, potassium chloride is the highest.

Butanol can form hydrogen bonding with the water despite having a carbon chain. Thus, butanol will be at second.

Taking about, ethane and propane, both are non polar and least likely to dissolve in water. But, the extent of the London forces increases with the increase in the molecular weight. So, propane will dissolve faster than ethane.

The order is:

Potassium chloride > Butanol >Propane > Ethane