What is the oxidation number of the molecular ion ammonium NH4+ in ammonium chloride NH4Cl?
Well, the oxidation number of nitrogen in
By definition, the oxidation number is the charge left on the central atom, when each of the bonding pairs of electrons are removed, with the charge assigned to the most electronegative atom. Nitrogen is more electronegative than hydrogen, so when we break a
Taken together, it is clear that the oxidation number of nitrogen in ammonium ion, is the same as the oxidation number of nitrogen in ammonia.
We could also formulate ammonium chloride as the hydrochloride adduct of ammonia, i.e.