Question

What is the oxidation number of `AgNO_3`?

Answer 1

Well, we break up the compound into its ions, and then into its atoms, and assign the elemental oxidation numbers.

Explanation:

Silver nitrate is composed of `NO_3^-` and `Ag^+"` ions. Clearly, `Ag^+` has a `+I` oxidation state. Why "clearly"?

For the gegenion, `NO_3^-`, the sum of the oxidation numbers equals the charge on the ion:

i.e. `N_"Oxidation number"+3xxO_"Oxidation number"=-1`.

The oxidation number of `O` is usually `-II` and it is here. And thus `N_"oxidation number"=+V`. Note that here nitrogen assumes its maximum oxidation number, the Group oxidation number `+V`. Nitrates are highly oxidizing species, though often its oxidizing potential is masked in aqueous solution.