The Prussian blue complex formed in the Lassaigne's test for nitrogen has the chemical formula . Wha — Practical Organic Chemistry and Purification Chemistry Question

💡 Solution & Explanation

In Prussian blue, $Fe_4[Fe(CN)_6]_3$, the iron outside the coordination sphere is Iron(III), so its oxidation state is $+3$. The complex anion is $[Fe(CN)_6]^{4-}$, where $CN$ is $-1$, making the iron inside the coordination sphere Iron(II) with an oxidation state of $+2$. The sum is $3 + 2 = 5$.