Ligand Substitution and Redox Reactions in Transition Metals

Ligand substitution reaction of [Cu(H₂O)₆]²⁺ with excess NH₃

[Cu(H₂O)₆]²⁺ + 4NH₃ → [Cu(NH₃)₄(H₂O)₂]²⁺ + 4H₂O (deep blue solution)

Ligand substitution reaction of [Cu(H₂O)₆]²⁺ with Cl⁻

[Cu(H₂O)₆]²⁺ + 4Cl⁻ → [CuCl₄]²⁻ + 6H₂O (yellow solution)

Reaction of [Fe(H₂O)₆]²⁺ with OH⁻

[Fe(H₂O)₆]²⁺ + 2OH⁻ → Fe(H₂O)₄(OH)₂ + 2H₂O (green ppt)

Reaction of [Fe(H₂O)₆]³⁺ with OH⁻

[Fe(H₂O)₆]³⁺ + 3OH⁻ → Fe(H₂O)₃(OH)₃ + 3H₂O (brown ppt)

Reaction of [Cu(H₂O)₆]²⁺ with OH⁻

[Cu(H₂O)₆]²⁺ + 2OH⁻ → Cu(H₂O)₄(OH)₂ + 2H₂O (blue ppt)

Reaction of [Al(H₂O)₆]³⁺ with OH⁻

[Al(H₂O)₆]³⁺ + 3OH⁻ → Al(H₂O)₃(OH)₃ + 3H₂O (white ppt)

Effect of excess NaOH on Al(H₂O)₃(OH)₃

Al(H₂O)₃(OH)₃ + OH⁻ → [Al(OH)₄]⁻ + 3H₂O (ppt dissolves)

Effect of excess NH₃ on Cu(H₂O)₄(OH)₂

Cu(H₂O)₄(OH)₂ + 4NH₃ → [Cu(NH₃)₄(H₂O)₂]²⁺ + 2OH⁻ (deep blue solution)

Reaction of [Fe(H₂O)₆]³⁺ with Na₂CO₃

2[Fe(H₂O)₆]³⁺ + 3CO₃²⁻ → 2Fe(H₂O)₃(OH)₃ + 3CO₂ + 3H₂O (brown ppt + gas)

Reaction of [Cu(H₂O)₆]²⁺ with Na₂CO₃

[Cu(H₂O)₆]²⁺ + CO₃²⁻ → CuCO₃ + 6H₂O (blue-green ppt)

Redox reaction between Fe²⁺ and MnO₄⁻

MnO₄⁻ + 5Fe²⁺ + 8H⁺ → Mn²⁺ + 5Fe³⁺ + 4H₂O (purple → colorless)

Redox reaction between C₂O₄²⁻ and MnO₄⁻

2MnO₄⁻ + 5C₂O₄²⁻ + 16H⁺ → 2Mn²⁺ + 10CO₂ + 8H₂O

Catalysis of SO₂ to SO₃ by V₂O₅

V₂O₅ + SO₂ → V₂O₄ + SO₃; V₂O₄ + ½O₂ → V₂O₅

Catalysis of S₂O₈²⁻ and I⁻ by Fe²⁺

S₂O₈²⁻ + 2Fe²⁺ → 2Fe³⁺ + 2SO₄²⁻; 2Fe³⁺ + 2I⁻ → 2Fe²⁺ + I₂

Autocatalysis of Mn²⁺ formation

2MnO₄⁻ + 5C₂O₄²⁻ + 16H⁺ → 2Mn²⁺ + 10CO₂ + 8H₂O (Mn²⁺ speeds up reaction)