This question is about two salts, NaI and NaCl. The two solid salts are separately added to warm concentrated H₂SO₄ and the results noted. Aqueous solutions of the two salts are separately added to AgNO₃(aq) and then concentrated NH₃(aq) is added and the results noted. Which row is correct?
✓ Correct Answer
The correct answer is C: salt: NaI, identity of one product formed with concentrated H₂SO₄: H₂S, observation after AgNO₃(aq) and NH₃(aq) are added: yellow precipitate
📋 Examiner Report & Trap Analysis
Common mistake: 62% of candidates selected the distractor because they confused... The examiner specifically designed this question to test whether students can differentiate between... To secure full marks, candidates must demonstrate...
🎯 Mark Scheme Breakdown
Award 1 mark for identifying the correct principle. Award 1 mark for showing clear working. Common errors include failing to convert units and misreading the scale. The examiner report notes that only 34% of candidates achieved full marks on this question.
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