What is the oxidation state of iron?
FeC2O4
The correct answer and explanation is :
In the compound iron(II) oxalate, FeC₂O₄, the oxidation state of iron (Fe) is +2.
Explanation:
Iron oxalate consists of iron (Fe) and the oxalate ion (C₂O₄²⁻). Let’s break this down to understand how to determine the oxidation state of iron.
- Oxalate Ion (C₂O₄²⁻):
- The oxalate ion is a bidentate ligand (meaning it can form two bonds), consisting of two carbon atoms and four oxygen atoms.
- The overall charge of the oxalate ion is 2-.
- Oxygen generally has an oxidation state of -2. Therefore, for the four oxygen atoms in the oxalate ion, the total oxidation state contribution is 4 × (-2) = -8.
- Let’s assume that the oxidation state of carbon (C) in the oxalate ion is +3 (since each carbon atom in oxalate generally has an oxidation state of +3).
- Now, the total oxidation state of the oxalate ion is:
( 2 \times (+3) + 4 \times (-2) = +6 – 8 = -2 ), which matches the overall charge of the oxalate ion (C₂O₄²⁻).
- Iron (Fe):
- In iron(II) oxalate, iron is bonded to the oxalate ion.
- Since the oxalate ion carries a charge of -2, and the overall compound is neutral, the oxidation state of iron (Fe) must balance out the charge of the oxalate ion.
- Therefore, the oxidation state of iron must be +2 to neutralize the negative charge of the oxalate ion, since ( +2 + (-2) = 0 ).
Conclusion:
The oxidation state of iron (Fe) in FeC₂O₄ is +2, meaning it is in the +2 oxidation state (Fe²⁺). This is characteristic of iron(II) compounds.