The solubility of a substance (how much solute can dissolve in a solvent) depends on several factors.
Factors Affecting Solubility:
- Nature of Solute and Solvent
- “Like dissolves like” → Polar solutes dissolve better in polar solvents (e.g., salt in water), while non-polar solutes dissolve better in non-polar solvents (e.g., oil in benzene).
- Temperature
- For most solids in liquids, solubility increases as temperature increases (e.g., more sugar dissolves in hot tea than cold tea).
- For gases in liquids, solubility decreases with increasing temperature (e.g., cold soda holds more carbon dioxide than warm soda).
- Pressure (mainly affects gases)
- Higher pressure increases the solubility of gases in liquids.
- Example: Carbonated drinks are bottled under high pressure to keep more CO₂ dissolved.
- Particle Size (surface area)
- Smaller particles dissolve faster because of a larger surface area in contact with the solvent.
- Agitation (Stirring or Shaking)
- Stirring helps distribute solute particles and increases the rate of dissolution, though it doesn’t change the maximum solubility.
- Presence of Other Substances
- Impurities or common ions in the solvent can increase or decrease solubility (e.g., “common ion effect” reduces solubility of salts).
In short: Solubility depends on the nature of solute and solvent, temperature, pressure (for gases), particle size, agitation, and presence of other substances.