Final Answer:
The nitrite ion NO⁻² is oxidized. Option 1 is correct.
Step-by-step explanation:
In chemical reactions, oxidation involves the loss of electrons, while reduction involves the gain of electrons. To determine whether the nitrite ion is oxidized or reduced, we can examine the change in oxidation state of nitrogen.
The oxidation state of nitrogen in the nitrite ion NO⁻² is +3. This can be calculated by assigning a value to each element's oxidation state in a compound: oxygen is typically -2, and the overall charge of the ion is -1. Given that there are two oxygen atoms with a combined oxidation state of -4, the oxidation state of nitrogen is +3 to balance the charge. If nitrogen undergoes a reaction and its oxidation state increases, it is oxidized.
In many reactions, nitrite NO⁻² can be further oxidized to form nitrate NO⁻³-. In this process, nitrogen goes from an oxidation state of +3 to +5. The increase in the oxidation state indicates that the nitrite ion is indeed oxidized. Therefore, the correct answer is that the nitrite ion NO⁻² is oxidized.