When an organic compound containing sulphur is fused with sodium and treated with aqueous sodium nit — Qualitative and Quantitative Analysis Chemistry Question

💡 Solution & Explanation

Sodium nitroprusside is $Na_2[Fe(CN)_5NO]$. Upon reacting with the sulphide ion ($S^{2-}$), it forms sodium thionitrosyl complex, $Na_4[Fe(CN)_5NOS]$, which exhibits the violet color. Because it requires 4 $Na^+$ cations to balance, the overall charge on the complex anion sphere $[Fe(CN)_5NOS]$ is $-4$. (Answer submitted as 4 or -4; standard magnitude is 4).