Three Main Types of Solutions: True, Colloidal, and Suspension

Solutions in chemistry are classified based on the size of the solute particles and their behaviour in the solvent. The three main types are:

1. True Solution

A true solution is a homogeneous mixture with tiny solute particles (less than 1 nanometer). These particles are uniformly distributed and do not settle over time.

• Particle size: < 1 nm

• Appearance: Transparent

• Examples: Salt in water, sugar in water

• Properties:

  • Does not scatter light

  • Cannot be separated by filtration

  • Stable and clear

2. Colloidal Solution

Colloids are intermediate between true solutions and suspensions. The particles (1–1000 nm) are not large enough to settle but can scatter light (Tyndall effect), giving a cloudy appearance.

• Particle size: 1–1000 nm

• Appearance: Cloudy but stable

• Examples: Milk, starch in water, fog

• Properties:

  • Shows the Tyndall effect

  • Cannot be filtered

  • Appears homogeneous to the naked eye, but is heterogeneous microscopically

3. Suspension

Suspensions are heterogeneous mixtures with large solute particles that are visible and settle over time if left undisturbed.

• Particle size: > 1000 nm

• Appearance: Heterogeneous and turbid

• Examples: Sand in water, muddy water

• Properties:

• Particles settle on standing

• Can be separated by filtration

• Does not show the Tyndall effect clearly

Summarised Table of The Three Main Types of Solutions

Understanding these types of solutions is fundamental in chemistry. Each has unique properties that determine its behaviour and applications in real-world scenarios, such as pharmaceuticals, food science, and environmental studies.