If α is the degree of dissociation of Na2SO4, the vant Hoff’s factor

• Solutions

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

1. 1 + 2α
2. 1 - α
3. 1 + α
4. 1 - 2α

Answer

Na₂SO₄ ↔ 2Na⁺ + SO₄^2–

1               0          0

1 – α         2α        α

Vant Hoff factor (i) = (1 – α + 2α + α)/1

= 1 + 2α

The correct option is A.