For example, sodium chloride in water is a true solution. Most ionic compounds form true solutions in water. Organic compounds like sugar and urea also form true solutions in water.
Suspensions
A suspension is a heterogeneous mixture in which one or more components have a particle size greater than 10-5cm. Very often these particles are visible to the naked eye.For example, sand in water, sodium chloride in benzene, turmeric in water etc.
Colloids
A colloid is a solution in which the particle size ranges between 10-7 and 10-5 cm.For example, milk, blood, honey, smoke, ink, gum, starch solution etc.
Difference between true solutions, suspensions and colloids
| Property | True solutions | Colloidal solutions | Suspensions |
|---|---|---|---|
| Particle size | Less than 10 - 7 cm | Between 10 - 5 and 10 - 7 cm | Greater than 10 - 5 cm |
| Visibility of particles | Invisible to naked eye not visible under powerful microscope | Invisible to naked eye. Visible under powerful microscope | Easily visible |
| Sedimentation of particles | Do not settle down | Settle down under high centrifugation | Settle down due to gravity |
| Filtration through filter paper | No residue is formed | No residue is formed | Residue is formed |
