(i) A + Na2CO3 -> B + C, (ii) A --CO2--> (Milky) C. The chemical formula of A and B are respectively — Qualitative and Quantitative Analysis Chemistry Question

💡 Solution & Explanation

Step 1: Reaction (ii) indicates that passing CO2 gas through compound A produces a milky white precipitate C. This is the classic limewater test, identifying A as calcium hydroxide (Ca(OH)2) and C as calcium carbonate (CaCO3). Step 2: Substitute Ca(OH)2 (A) into reaction (i): Ca(OH)2 + Na2CO3 ---> 2 NaOH (B) + CaCO3 (C). This is a double displacement reaction that produces sodium hydroxide (NaOH) as compound B. Step 3: Thus, the chemical formulas of A and B are Ca(OH)2 and NaOH respectively, corresponding to option (b).