Which species could be reduced to form NO2?A.     N2OB.     NO3−C.     HNO2D.     NO

The species that could be reduced to form NO2 is NO3− (B).

Here's the step-by-step explanation:

Reduction is a chemical reaction that involves the gaining of electrons. When a molecule is reduced, it gains electrons, which decreases its oxidation state.

1. N2O: The nitrogen in N2O is already at a lower oxidation state (+1) than in NO2 (+4). Therefore, N2O cannot be reduced to NO2.

2. NO3−: The nitrogen in NO3− is at a higher oxidation state (+5) than in NO2 (+4). Therefore, NO3− can be reduced to NO2.

3. HNO2: The nitrogen in HNO2 is already at the same oxidation state (+3) as in NO2 (+4). Therefore, HNO2 cannot be reduced to NO2.

4. NO: The nitrogen in NO is at a lower oxidation state (+2) than in NO2 (+4). Therefore, NO cannot be reduced to NO2.

So, the correct answer is B. NO3−.