Question

How will you test a colloid?

Answer 1

A colloid can be tested by the Tyndall effect.

• If the sample of solution shows the Tyndall effect, then the given sample of solution is a colloid otherwise it is not a colloid.

Colloid: A colloid is a heterogeneous mixture in which the particles cannot be seen with the naked eye.

• The diameter of the particles of colloids lies in the range of ${10}^{-6}-{10}^{-9}\mathrm{m}$.
• Example: Milk, blood, butter etc.

Tyndall effect: When the particles can scatter a beam of light passing through them and make the path of light visible, it is known as the Tyndall effect.

• The light is scattered when light collides with the colloidal particles and deviates from its normal straight line path.
• This scattering makes the path of the light beam visible, as illustrated below.