Question

Write a short note on Coagulation.

Hint:

Lyophobic colloids are easily coagulated by electrolytes due to weak solvation.

Answer 1

Step 1: Definition.
Coagulation is the process of aggregation of colloidal particles, resulting in the settling down (precipitation) of colloids. It occurs when the stability of the colloidal system is disturbed.
Step 2: Causes of coagulation.
\begin{enumerate} \item By addition of electrolytes: Electrolyte ions neutralize the charges on colloidal particles, causing them to aggregate. \item By mutual coagulation: Mixing two oppositely charged sols can neutralize charges, causing precipitation. \item By boiling: Heating increases particle collisions and reduces stability. \item By electrophoresis: Charged particles move towards the oppositely charged electrode and get coagulated. \end{enumerate} Conclusion:
Coagulation is the destruction of colloidal stability, leading to precipitation of particles.