2(a) Test Observation Inference Add dilute HNO₃ and filter Effervescence observed. Colourless gas evolved which turns lime water milky. CO₂ evolved. Carbonate present. 2(b)(i) Test Observation Inference Add NaOH(aq) dropwise and in excess Light blue precipitate formed, insoluble in excess. Cu²⁺ present. 2(b)(ii) Test Observation Inference Add NH₃(aq) dropwise and in excess Light blue precipitate formed which dissolves in excess to give deep blue solution. Cu²⁺ present. 2(c) Observation: Brown solution obtained after addition of iodine solution. Inference: Starch present. Verified Chemistry Practical Questions 👇🏿

You're on a roll — let's verify your observations and inferences. 2(a) Add dilute HNO_3 and filter: Observation: Effervescence observed. Colourless gas evolved which turns limewater milky. Inference: CO_2 evolved. Carbonate present. Verification: ✅ Correct. The reaction of a carbonate with an acid produces carbon dioxide gas, which turns limewater milky. 2(b)(i) Add NaOH(aq) dropwise and in excess: Observation: Light blue precipitate formed, insoluble in excess. Inference: Cu^2+ present. Verification: ✅ Correct. Copper(II) ions form a light blue precipitate of copper(II) hydroxide with NaOH, which is insoluble in excess NaOH. 2(b)(ii) Add NH_3(aq) dropwise and in excess: Observation: Light blue precipitate formed which dissolves in excess to give deep blue solution. Inference: Cu^2+ present. Verification: ✅ Correct. Copper(II) ions form a light blue precipitate of copper(II) hydroxide with NH_3, which then dissolves in excess NH_3 to form a deep blue solution of the tetraamminecopper(II) complex ion. 2(c) Observation: Brown solution obtained after addition of iodine solution. Inference: Starch present. Verification: ❌ Incorrect. Observation: A brown solution obtained after the addition of iodine solution means that the iodine solution's original color (brown/yellow) persists. Correct Inference: Starch is absent. If starch were present, the solution would turn blue-black*. What's next? Send 'em!