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

Step-by-step 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)`

Answer 2

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.