The Number of ions formed on dissolving one molecule of FeSO₄ (NH₄)2SO₄.6H₂O is?

5

The correct answer is (3).

The compound FeSO₄ (NH₄)2SO₄.6H₂O is a double salt. When it dissolves in water, it dissociates into five ions:

Fe²⁺

2 SO₄^2-

2 NH₄⁺

The dissociation can be represented as:

\(FeSO_4 (NH_4)_2SO_4 6H_2O → Fe^{2+} + 2SO_4^{2-} + 2NH_4^{+} + 6H_2O\)

Therefore, the number of ions formed on dissolving one molecule of FeSO₄ (NH₄)2SO₄.6H₂O is 5.