Question

What is coagulation? Explain the Hardy and Schulze rules.

Answer 1

Hint:A colloid is a mixture having particles whose dimension or diameter range from 1 to 1000 nanometres and the particles remain evenly dispersed throughout the solution.

Complete step by step answer:
The term coagulation refers to the precipitation of the colloids by removing their residual charges. The colloidal particles carry a charge on their surface due to which the particles are stable. The electrostatic charges between the similarly charged particles prevent them from coming close to each other and get precipitated. When the charge is removed, the particles come closer to each other and thus they precipitate.
The Hardy and Schulze rules state that: The definite amount of electrolyte required for the coagulation of a definite quantity of colloid is dependent on the valance of the coagulating ion. The rules are listed as below:
-The ions of the electrolyte that cause the coagulation carry a charge that is opposite to the charge of the ions of the colloid.
-The higher the valence of the coagulating ion, the higher is its ability to facilitate coagulation.

Note:
To be classified as a colloid, the substance in the dispersed phase must be larger than the size of the molecules but smaller than what can be seen with the naked eye. There are different types of colloids such as the ‘sol”, which is a colloidal suspension with solid particles in a liquid. The “Emulsion” is formed from two different liquids. “Foam” is formed when many gas particles are trapped in a liquid or a solid. “Aerosol” contains small particles of liquid or solid dispersed in a liquid.