Question

What is the oxidation state of iron in haemoglobin?

• A. $F{e}^{-}$
• B. $F{e}^{2+}$
• C. $F{e}^{3+}$
• D. $F{e}^{4+}$

Answer 1

Answer: (B)

$F{e}^{2+}$

The iron in hemoglobin must be in the ferrous (+2) state to bind oxygen. If the iron of hemoglobin becomes oxidised to the ferric (+3) state, the corresponding hemoglobin, called methemoglobin, cannot bind oxygen.

So, the correct answer is " Fe${}^{+2}$