Question

Calculate van’t Hoff factor of the following solutions 

1. Al₂(SO₄)₃ is dissolved in water 

2. MgCl₂ is dissolved in water 

3. Benzoic acid is dissolved in benzene 

4. Glucose is dissolved in water 

5. 10 gm of KCl is dissolved in 1 Litre of water

Answer 1

1.When Al₂(SO₄)₃ is dissolved in water, its one molecule dissociates into 2 Al³⁺ ions and 3 SO₄ ^2- ions, so its van’t Hoff factor for this is 5. 

2. When MgCl₂ is dissolved in water, its one molecule dissociates into 1 Mg²⁺ ions and 2 Clions, so its van’t Hoff factoris 3. 

3.When benzoic acid is dissolved in benzene, its two molecule associate to form a dimer. Therefore, its van't Hoff factor is 1/2.

4. Glucose does not undergo association or dissociation, hence van’t 'Hoff factor for glucose is 1. 

5.When KCl is dissolved in water, its every molecule dissociates in two ions. So its van’t Hoff factor for this is 2.