Cr₂(SO₄)₃ +3 Na₂S= Cr₂S₃↓+3 Na₂SO₄
2Cr³⁺+3(SO₄)²⁻+6Na⁺+3S²⁻= Cr₂S₃↓+6 Na⁺+3(SO₄)²⁻
2Cr³⁺+3S²⁻= Cr₂S₃↓
Cr₂(SO₄)₃ +3 Na₂S= Cr₂S₃↓+3 Na₂SO₄
2Cr³⁺+3(SO₄)²⁻+6Na⁺+3S²⁻= Cr₂S₃↓+6 Na⁺+3(SO₄)²⁻
2Cr³⁺+3S²⁻= Cr₂S₃↓