Solubility is the maximum amount of solute that can dissolve in a given amount of solvent at a specific temperature and pressure. For solid–liquid solutions (like sugar or salt in water), solubility can be increased by the following methods:
1. Increasing Temperature
- For most solids, solubility increases with temperature because higher temperature gives solvent molecules more kinetic energy.
- This allows them to break solute particles apart more effectively.
- Example: More sugar dissolves in hot tea than in cold tea.
2. Stirring or Agitation
- Stirring spreads solute particles throughout the solvent, speeding up dissolution.
- It doesn’t change the maximum solubility but helps reach it faster.
3. Particle Size Reduction
- Crushing or grinding the solute increases its surface area in contact with the solvent.
- This allows more solvent molecules to interact with solute particles, increasing the rate of dissolving.
4. Using a Suitable Solvent (Like Dissolves Like)
- Polar solutes dissolve better in polar solvents (e.g., salt in water).
- Non-polar solutes dissolve better in non-polar solvents (e.g., iodine in alcohol).
- Choosing the correct solvent can increase solubility significantly.
5. Applying Pressure (for some cases)
- Pressure doesn’t usually affect solid–liquid solubility much (it mainly affects gases in liquids).
- However, in rare cases, pressure can slightly increase solubility.