1. 4Al + 3O2 = 2Al2O3
2. Al2O3 + 3H2SO4 = Al2(SO4)3 + 3H2O
Al2O3 + 6H⁺ + 3SO4²⁻ = 2Al³⁺ + 3SO4²⁻ + 3H2O
Al2O3 + 6H⁺= 2Al³⁺ + 3H2O
3. Al2(SO4)3 + 6NaOH = 2Al(OH)3 + 3Na2SO4
2Al³⁺ + 3SO4²⁻ + 6Na⁺ + 6OH⁻ = 2Al(OH)3 + 6Na⁺ + 3SO4²⁻
Al³⁺ + 3OH⁻ = Al(OH)3
4. 2Al(OH)3 = Al2O3 + 3H2O