Answer to Question #349306 in General Chemistry for soph

Question

4. Balance the following redox reaction in a basic solution. Use any method you prefer (oxidation number method or half reaction method). Ce4+ + I –  Ce3+ + IO3 –

Answer 1

Solution:

Half-reaction method:

Unbalanced chemical equation: Ce⁴⁺ + I⁻ → Ce³⁺ + IO₃⁻

Oxidation half-reaction:

I⁻ + 6OH⁻ − 6e⁻ → IO₃⁻ + 3H₂O

Reduction half-reaction:

Ce⁴⁺ + e⁻ → Ce³⁺

Balanced chemical equation: 6Ce⁴⁺ + I⁻ + 6OH⁻ → 6Ce³⁺ + IO₃⁻ + 3H₂O

Oxidation number method:

Unbalanced chemical equation: Ce⁴⁺ + I⁻ → Ce³⁺ + IO₃⁻

I⁻¹ − 6e⁻ → I⁺⁵

Ce⁴⁺ + e⁻ → Ce³⁺

Balanced chemical equation:

6Ce⁴⁺ + I⁻¹ → 6Ce³⁺ + I⁺⁵

or

6Ce⁴⁺ + I⁻ + 6OH⁻ → 6Ce³⁺ + IO₃⁻ + 3H₂O