redox half equation VO43- to V2+
Answers
Oxidation is the loss of electrons; the oxidation state decreases
Reduction is the gain of electrons; the oxidation state increases
An oxidising agent oxidises something and is itself reduced
A reducing agent reduces something and is itself oxidised
e.g. Fe2O3 + 3 CO → 2 Fe + 3 CO2
Rules for balancing redox reactions
1. Use oxidation states to identify the species undergoing oxidation or reduction.
Fe2O3 → Fe reduction CO → CO2 oxidation
2. Balance the atoms undergoing oxidation or reduction.
Fe2O3 → 2 Fe CO → CO2
3. Balance the oxygen atoms by adding H2O.
Fe2O3 → 2 Fe + 3 H2O H2O + CO → CO2
4. Balance the hydrogen atoms by adding H+
.
6 H+ + Fe2O3 → 2 Fe + 3 H2O H2O + CO → CO2 + 2 H+
5. Balance the electrons.
6 e– + 6 H+ + Fe2O3 → 2 Fe + 3 H2O 2 e
– + H2O + CO → CO2 + 2 H+
6. Multiply either half equation to make sure that the no. of electrons in each half
equation match.
6 e– + 6 H+ + Fe2O3 → 2 Fe + 3 H2O 6 e
– + 3 H2O + 3 CO → CO2 + 6 H+
7. Combine to get the full redox equation.
6 e– + 6 H+ + Fe2O3 + 3 H2O + 3 CO → 2 Fe + 3 H2O + 3 CO2 + 6 H+ + 6 e–
8. Cancel out anything that appears on both sides of the equation.
6 e
– + 6 H+ + Fe2O3 + 3 H2O + 3 CO → 2 Fe + 3 H2O + 3 CO2 + 6 H+ + 6 e–
Fe2O3 + 3 CO → 2 Fe + 3 CO2