Question

Which one among the following will show the Tyndall effect?

(i) Common salt solution

(ii) Copper sulphate solution

(iii) Milk

Answer 1

Hint: The scattering of a light beam when it is passed through a solution or medium containing small suspended particles (colloidal particles) is called Tyndall effect. Smoke is the best example which shows the Tyndall effect.

Complete step by step answer:

In the question it is asked which solution is going to exhibit the Tyndall effect among the given options.

Coming to the given solutions in the question.

(i) Common salt solution: Sodium chloride is also called common salt. It does not show the Tyndall effect because the size of the ions produced by the common salt in the water is less than 1 nm.

 

(ii) Copper sulphate solution: It does not show the Tyndall effect because the size of the ions produced by the copper sulphate in the water are less than 1 nm.

(iii) Milk: Milk is a suspension (one phase is suspended in another phase). Fat is suspended in milk and milk shows the Tyndall effect due to the presence of the suspended particles whose size is greater than 1nm.

- Therefore Milk suspension shows Tyndall effect among the given chemicals.

Note: Generally if the ion size is very small then they won’t scatter the light and do not show the Tyndall effect. Common salt and copper sulphate solutions are true solutions (where the size of the ions is less than 1 nm) and do not show the Tyndall effect.