what is the n-factor for co₂ in the decomposition of caco3

Determine the n-factor for CO₂ in the reaction:

CaCO₃(s) → CaO(s) + CO₂(g)

• In carbonate (CO₃²⁻): let C = x → x + 3(−2) = −2 ⇒ x = +4
• In CO₂: x + 2(−2) = 0 ⇒ x = +4

Carbon remains at +4 in both species → no redox change.

For non-redox species, n-factor is taken from their acid–base capacity (replaceable H⁺ or neutralizable OH⁻).

CO₂ is an acidic oxide that forms carbonic acid in water:

CO₂ + H₂O ⇌ H₂CO₃

H₂CO₃ is dibasic (can donate 2 H⁺).

Final Answer

n-factor of CO₂ (for this context) = 2.