Question

The complex $\left[Fe\right(H_{2}O{)}_{3}NO{]}^{+}$ is formed in the ring test for nitrate ion when freshly prepared $FeS{O}_4$ solution is added to aqueous solution of $N{O}_3$ followed by addition of $conc.H_{2}S{O}_4$: This complex is formed by charge transfer in which of the following:

• A. $F{e}^{2+}$ changes to $F{e}^{3+}$ and $N{O}^{+}$ changes to $NO$
• B. $F{e}^{2+}$ changes to $F{e}^{3+}$ and $NO$ changes to $N{O}^{2+}$
• C. $F{e}^{2+}$ changes to $F{e}^{3+}$ and $NO$ changes to $N{O}^{+}$
• D. No charge transfer takes place

Answer 1

The correct option is C $F{e}^{2+}$ changes to $F{e}^{3+}$ and $NO$ changes to $N{O}^{+}$

$F{e}^{2+}+e^{-}\to F{e}^{+}$
$NO\to N{O}^{+}+e^{-}$
Based on magnetic properties of the comply is found that iron has three unpaired Sett thus it exists as $F{e}^{+}$ formed by reduction of $F$ by $NO$ which is oxidised to $N{O}^{+}$.