Question

How is a colloidal solution of starch prepared? Why is the mixture stirred constantly while adding boiling water?

Answer 1

Dear User,
Colloidal solution of starch is prepared by the following way :

1. Take 50 mL of distilled water in a beaker and heat it to about 100ºC.
2. Add a thin paste of starch to the water with constant stirring.
3. A colourless white sol will be obtained.

The mixture is stirred constantly while adding boiling water because increasing temperature increases the solubility of the starch in water and constant stirring is required so that no lumps formation takes place.