What is the oxidation number of iron in Fe2O3?A.+6B.+2C.+4D.+3

The oxidation number of iron in Fe2O3 is +3. So, the correct answer is D. +3.

Here's the step-by-step explanation:

1. The oxidation number of oxygen (O) is usually -2.
2. In Fe2O3, there are three oxygen atoms, so the total oxidation number for oxygen is 3*(-2) = -6.
3. The total oxidation number of a neutral compound is zero.
4. Therefore, the total oxidation number for iron (Fe) in Fe2O3 must be +6 (to counterbalance the -6 from oxygen).
5. Since there are two iron atoms in Fe2O3, the oxidation number for each iron atom is +6/2 = +3.