Answer to Question #345845 in General Chemistry for Meg

Question

Write half-reactions for each of the following redox reactions. Identify each half-reaction as being either oxidation or reduction. Show your work.

A. SnS2(s) + O2(g) —> SnO2(s) + SO2(g)

B. Mg(s) + N2(g) —> Mg3N2(s)

Answer 1

Solution:

(A):

Unbalanced chemical equation: SnS₂(s) + O₂(g) → SnO₂(s) + SO₂(g)

Oxidation half-reaction:

S²⁻ − 2e⁻ → S⁴⁺

Reduction half-reaction:

O₂⁰ + 4e⁻ → 2O⁻²

Net reaction:

2S²⁻ + O₂⁰ → 2S⁴⁺ + 2O⁻²

Balanced chemical equation: SnS₂(s) + 3O₂(g) → SnO₂(s) + 2SO₂(g)

(B):

Unbalanced chemical equation: Mg(s) + N₂(g) → Mg₃N₂(s)

Oxidation half-reaction:

Mg⁰ − 2e⁻ → Mg²⁺

Reduction half-reaction:

N₂⁰ + 6e⁻ → 2N⁻³

Net reaction:

3Mg⁰ + N₂⁰ → 3Mg²⁺ + 2N⁻³

Balanced chemical equation: 3Mg(s) + N₂(g) → Mg₃N₂(s)