Question

Analyse the following statements :

Statement 1 : Negatively charged Arsenic sulphide can be effectively precipitated using Al^- ion than Na⁺ ion.

Statement 2 : There is no difference in the precipitation of arsenic sulphide by Al³⁺ ion and Na⁺ ion.

1. Which statement is correct? Justify. 

2. Name the law behind your opinion. 

3. State the law.

Answer 1

1. Statement 1. Precipitating power of an ion is directly proportional to its valency.

2. Hardy-Schulze rule.

3. A colloid can be precipitated by an ion having opposite charge to that of the colloid. Greaterthe valency of coagulating ion added greater its power to precipitate.

eg : AI³⁺> Mg²⁺ > SO₄^2- > Na⁺ > PO³⁺> Cl^-