Can Someone Explain to Me What n Factor/valency Factor is? With Some Examples

n factor or valency factor describes the number of electrons which is lost or gained per atom in a redox reaction. The reaction between potassium chromate and iron sulphate and the reaction between zinc and copper sulphate are the few examples.

n Factor or Valency Factor

• In redox processes, the phrase “n factor” or “valency factor” is employed. It is a term used to express how many electrons per atom are gained or lost during a process.
• Assume that the displacement reaction between zinc and copper sulphate solution occurs.

Zn (s) + CuSO₄ (aq) → ZnSO₄ (aq) + Cu(s)

Here Zn loses two electrons to become Zn²⁺. So the n factor for zinc is 2

• The reaction between potassium chromate and iron sulphate is another example.

6FeSO₄ + K₂Cr₂O₇ + 7H₂SO₄ → 3Fe₂(SO₄)₃ + K₂SO₄ + Cr₂(SO₄)₃ + 7H₂O

The Fe⁺² is oxidized to Fe⁺³ by losing one electron. So the n factor for FeSO₄ is 1

• If we take into account the subsequent reaction of oxalic acid dissociation, the n factor for an organic acid like oxalic acid.

COOH – COOH → 2CO₂ + 2H⁺ + 2e^–

Oxalic acid has two interchangeable hydrogen ions, hence its n factor is two.