How many following metals evolve NO (Nitric oxide) gas with dil. HNO3 (20%)? Hg, Cu, Pb, Zn, Fe, Al, — Redox Reactions and Volumetric Analysis Chemistry Question

💡 Solution & Explanation

Step 1: Identify the reactants. Strontium oxalate, SrC2O4↓, is an insoluble salt, and HCl is a strong mineral acid. Step 2: Analyze the protonation reaction. The strong acid HCl provides a high concentration of protons that fully protonate the oxalate ions, dissolving the strontium oxalate to form soluble strontium chloride (SrCl2) and oxalic acid (H2C2O4). Step 3: Because the insoluble strontium oxalate precipitate is dissolved, this reaction is classified as a precipitate dissolution reaction (type B). Thus, the correct option is (b).