Answer:
0.78 M for SO₄²⁻
Explanation:
The chemical formula for aluminium sulfate is Al₂(SO₄)₃
So for a concentration of 0.26 M you have in solution 0.26 moles of Al₂(SO₄)₃ in 1 liter of solution.
But you have three times more sulfate ions SO₄²⁻ in solution, so the molar concentration for this ion will be:
0.26 × 3 = 0.78 M
