Question

Iron does not exhibit ___________ oxidation state.

• A. $+6$
• B. $+4$
• C. $+3$
• D. $+5$
• E. $+2$

Hint:

Iron most commonly exhibits oxidation states of $+2$ and $+3$, while higher oxidation states are rare.

Answer 1

The Correct Option is D

Step 1: Iron commonly exhibits oxidation states of $+2$ and $+3$, as seen in compounds such as FeO and Fe$_2$O$_3$. 
Step 2: Iron can also exhibit oxidation states of $+4$ and $+6$ in compounds such as FeO$_2$ and ferrates (FeO$_4^{2-}$). 
Step 3: However, iron does not commonly exhibit the $+5$ oxidation state, as no stable compounds with Fe$^{+5}$ are known. 
Step 4: Therefore, the correct answer is (D).