The oxidation state of iron in Na4[Fe(CN)5(NOS)] is : — Coordination Compounds Chemistry Question

💡 Solution & Explanation

Step 1: Sodium nitroprusside reacts with sulfide ions to form the purple-colored complex Na4[Fe(CN)5(NOS)]. Step 2: In this complex, the thionitrosyl ligand (NOS^-) carries a -1 charge, and each cyano group carries a -1 charge. Step 3: Let the oxidation state of Fe be x: 4*(+1) + x + 5*(-1) + 1*(-1) = 0 => 4 + x - 5 - 1 = 0 => x = +2, matching option (b).