In NH4NO2, we have two parts: the ammonium ion NH4+ and the nitrite ion NO2- . Let's find the oxidation state of nitrogen in each part.1. Ammonium ion NH4+ :In this ion, nitrogen is bonded to four hydrogen atoms. Hydrogen has an oxidation state of +1. Therefore, the total positive charge contributed by the hydrogen atoms is +4. Since the overall charge of the ammonium ion is +1, the oxidation state of nitrogen in NH4+ must be -3 to balance the charge.2. Nitrite ion NO2- :In this ion, nitrogen is bonded to two oxygen atoms. Oxygen has an oxidation state of -2. Therefore, the total negative charge contributed by the oxygen atoms is -4. Since the overall charge of the nitrite ion is -1, the oxidation state of nitrogen in NO2- must be +3 to balance the charge.So, the oxidation states of nitrogen in NH4NO2 are -3 in the ammonium ion and +3 in the nitrite ion.