Rani got a cut on her finger while working in the kitchen. She applied an antiseptic liquid to stop bleeding but it was not effective. Her husband asked her to rub alum on the cut. To her surprise, the bleeding stopped.

(a) Why was the antiseptic liquid not effective ?

(b) What was the use of alum here ?

(c) Who according to you has a proper knowledge of colloidal solutions - Rani or her husband ?

When a beam of light was passed through the solution of a substance 'X' dissolved in water, the path of light could be seen. What is the nature of this solution ?

Identify colloids from the following :
Copper sulphate solution, milk, smoke, muddy water, butter, sugar solution, face cream, lemonade, jelly, soda water.

Identify the dispersed phase and dispersion medium in the following examples of colloids :

(a) Fog

(b) Cheese

(c) Coloured gem stones