Question

Balance the reaction. A coefficient of "1" is understood. Choose option "blank" for the correct answer if the coefficient is "1." Al + O2 → Al2O3

Answer 1

Balanced chemical reaction: 4Al + 3O₂→ 2Al₂O₃.

a) Oxidation half-reaction: Al⁰ → Al⁺³ + 3e⁻ /×4; 4Al⁰ → 4Al⁺³ + 12e⁻.

b) Reduction half-reaction: 4e⁻ + O₂ → 2O⁻² /×3; 12e⁻ + 3O₂ → 6O⁻².

Oxidation is increase of oxidation number, aluminium change oxidation number from zero to +3 and reduction is decrease of oxidation number, oxygen from 0 to -2.

Answer 2

Explanation:

A balanced equation is an equation in which the number of atoms on both reactant and product side are equal.

For example, $Al + O_{2} \rightarrow Al_{2}O_{3}$

Number of atoms on reactant side are as follows.

• Al = 1

• O = 2

Number of atoms on product side are as follows.

• Al = 2

• O = 3

Therefore, in order to balance the given equation multiply Al by 2 and multiply $O_{2}$ by 3 on reactant side. Whereas multiply $Al_{2}O_{3}$ by 2 on product side.

Thus, the balanced chemical equation will be as follows.

                $4Al + 3O_{2} \rightarrow 2Al_{2}O_{3}$