Question

Determine the osmotic pressure of a solution prepared by dissolving 2.32 × 10^–2 g of K₂SO₄ in 2 L of solution at \(25 ^\circ \text{C}\), assuming that K₂SO₄ is completely dissociated.

(R = 0.082 L atm K^–1 mol^–1 , Molar mass K₂SO₄ = 174 g mol^–1 )

Answer 1

Concentration of K₂SO₄ solution \(= \frac{2.32 \times 10^{-2}}{174 \times 2} = 6.67 \times 10^{-5} \ \text{M}\) 

van’t Hoff factor, i = 3

Osmotic pressure, \(\pi = icRT\)

= 3 × 6.67 × 10^–5 × 0.082 × 298

= 4.89 × 10^–3 atm