Na2S2O3 + BaCl2 -> BaS2O3↓ + 2NaCl — Redox Reactions and Volumetric Analysis Chemistry Question

💡 Solution & Explanation

Step 1: Sodium thiosulfate, Na2S2O3, and barium chloride, BaCl2, are both highly soluble in water. Step 2: Upon mixing, barium ions react with thiosulfate ions to precipitate sparingly soluble white barium thiosulfate, BaS2O3↓. Step 3: Since a solid precipitate forms from soluble starting materials, this is classified as a precipitate formation reaction (type A), matching option (a).