Different types of solutions are classified based on the amount of solute dissolved in the solvent. It contains an excess of solute at a specific temperature, making it unstable. 

• A saturated solution holds the maximum amount of solute that can dissolve in the solvent at a particular temperature. It's at equilibrium, with no more solute able to dissolve. 
• An unsaturated solution has the capacity to dissolve more solute at a given temperature; it hasn't reached its maximum solubility yet. 

Additionally, solutions are categorized based on the solvent used. 

• An aqueous solution forms when a solute dissolves in water. An example is sugar dissolved in water. 
• A non-aqueous solution occurs when a solute dissolves in a solvent other than water. One example includes sulfur dissolved in carbon disulfide. 

Lastly, solutions can be classified based on the quantity of solute relative to the solvent. 

• A concentrated solution consists of a large amount of solute dissolved in a small volume of solvent. 
• A dilute solution contains a small amount of solute dispersed in a large volume of solvent.