Question

The brown ring complex, $\left[Fe\right(H_{2}O{)}_{5}N{O}^{+}]S{O}_4$ has oxidation number of Fe as :

• A. 1
• B. 2
• C. 3
• D. 4

Answer 1

The correct option is A 1

$NO$ in brown ring complex has $+1$ oxidation state.
Let oxidation state of Fe be $x$.
Since the overall charge on the coordination sphere, $\left[Fe\right(H_{2}O{)}_{5}N{O}^{+}]$ is $+2$, the sum of oxidation states of all elements in it should be equal to $+2$.
Therefore, $x+1=+2$
or, $x=+1$
Hence, the oxidation state of iron in the brown ring complex is $+1$.