Question

Which from following process does NOT results in coagulation?

• A. electrophoresis
• B. by adding excess solvent
• C. by mixing two oppositely charged sols
• D. by boiling

Hint:

Coagulation means the colloidal particles lose their charge and settle; check what each process does to the charge or stability of the sol.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept
Coagulation is the settling of colloidal particles when their stabilising charge is neutralised or removed.

Step 2: Check Each Process
Electrophoresis carries the particles to an electrode, where they lose charge and coagulate. Mixing two oppositely charged sols neutralises the charges and causes mutual coagulation. Boiling disturbs the adsorbed layer and charge, and the sol coagulates.

Step 3: Adding Excess Solvent
Adding more solvent only dilutes the sol and does not remove the charge on the particles, so it does not cause coagulation.

Step 4: Compare the options
The process that does NOT result in coagulation is 'by adding excess solvent'.

Final Answer:
Adding excess solvent does not cause coagulation. \[ \boxed{\text{(B) }\text{by adding excess solvent}} \]