The Nature of Solute and Solvent

The solubility of some solutes depends on the nature of the solute and solvent. Polar solvents dissolve polar solutes. Rubbing alcohol is a polar solvent while sugar is a polar solute so it dissolves in rubbing alcohol. On the other hand, mothballs dissolve in carbon tetrachloride (CCl₄) but not in water. Mothballs and CCl₄ are both nonpolar.

Temperature

Another factor that affects the solubility of some solutes is temperature. Solids are usually more soluble in liquids at higher temperatures. For instance, sugar dissolves faster in hot water than in cold.

What about the solubility of gases in liquids? Unlike solids or liquids, most gases become less soluble in liquids as the temperature increases. You might have observed at home that when you heat water, bubbles appear along the sides of the container where the water is being heated even before the water boils. These are simply bubbles of dissolved gases like O₂, N₂, and CO₂ escaping from water.