Question

You are supplied with the following chemicals NaCl, BaCl₂ , AlCl₃ .

1. Which of these would you prefer most to coagulate a sample of As₂S₃ sol?

2. Arrange the following electrolytes in the increasing order of coagulating power.

NaCl, BaCl₂ , AlCl₃

3. Name and state the rule based on which you have arrived at the coagulating power of these substances.

Answer 1

1. AlCl₃

2. NaCl < BaCl₂ < AlCl₃

3. Hardy – Schulze rule. It states that greater the valence of the flocculating ion greater is its power to cause precipitation.