How many following ammonium salts will evolve N2 gas on heating? (NH4)2CO3, (NH4)2Cr2O7, NH4NO2, NH4 — Redox Reactions and Volumetric Analysis Chemistry Question

💡 Solution & Explanation

Step 1: Identify the reactants. Ferrous cyanide, Fe(CN)2↓, is an insoluble yellowish-brown precipitate. Step 2: Observe the addition of potassium cyanide (KCN). Cyanide acts as a very strong ligand and coordinates with iron(II) to form the highly stable, water-soluble complex potassium ferrocyanide (K4[Fe(CN)6]). Step 3: Since the solid precipitate dissolves upon complexation to form a clear soluble solution, this is a precipitate dissolution reaction (type B). Thus, the correct option is (b).