Question

Oxidation number of iron in brown ring complex (obtained in ring-test of ${NO}_3^{-}$) is ?
Brown ring complex: ${\left[Fe{\left(H_{2}O\right)}_{5}NO\right]}^{2+}$

• A. 1
• B. 2
• C. 3
• D. 3.5

Answer 1

The correct option is A 1

Let $x$ be the oxidation number of iron in ${\left[Fe{\left(H_{2}O\right)}_{5}NO\right]}^{2+}$.
Since the overall
charge on the complex is $+2$, the sum of oxidation states of all elements in
it should be equal to $+2$.
Therefore, $x+5\left(0\right)+1=2$
or, $x=+1$
Thus, the oxidation number of iron in brown complex (obtained in ring-test of ${NO}_3^{-}$) ${\left[Fe{\left(H_{2}O\right)}_{5}NO\right]}^{2+}$ is $+1$.