AgI↓ + 2Na2S2O3 -> Na3[Ag(S2O3)2] + NaI — Redox Reactions and Volumetric Analysis Chemistry Question

💡 Solution & Explanation

Step 1: Identify starting materials: Silver iodide (AgI↓) is an extremely insoluble yellow precipitate. Step 2: Analyze the reaction with sodium thiosulfate (Na2S2O3): Despite the low solubility of AgI, the thiosulfate ion is an exceptionally strong ligand that drives the dissolution by forming a highly stable, soluble complex, Na3[Ag(S2O3)2]. Step 3: Since the insoluble precipitate dissolves to yield a clear solution, this is classified as a precipitate dissolution reaction (type B).