Q12(b). Activities of Na⁺ and SO₄²⁻ in a mixed electrolyte
An aqueous solution at 25 °C is 0.005 molal in sodium chloride and 0.001 molal in potassium sulphate. Calculate activities of Na⁺ and SO₄²⁻ ions. At 25 °C the Debye–Hückel constant A is equal to 0.509.
Answer in brief
I = 0.008 mol kg⁻¹; a(Na⁺) = 0.900 × 0.005 = 4.50 × 10⁻³; a(SO₄²⁻) = 0.657 × 0.001 = 6.57 × 10⁻⁴.
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CoversDebye–Hückel limiting lawionic strengthactivity coefficientactivity of ionselectrolyte solution
All parts of Question 12
- 12(a) Change in pH of an acetate buffer on adding HCl10 marks
- 12(b) Activities of Na⁺ and SO₄²⁻ in a mixed electrolyte10 marks