Question

If a is the degree of dissociation of Na2SO4, the vant Hoff’s factor (i) used for calculating the molecular mass is :

• A. 1 + a
• B. 1 – a
• C. 1 + 2a
• D. 1 – 2a.

Answer 1

Answer: (C)

1 + 2a

Answer 2

Na2SO4 $\rightleftharpoons$ 2Na+ + SO42–

1 0 0

1 – a 2a a

Vant Hoff factor (i) =$\frac{1 - \alpha + 2\alpha + \alpha}{1}1 + 2\alpha$