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The colours of fireworks are produced by chemicals - AQA - GCSE Chemistry - Question 7 - 2014 - Paper 3
Question 7
The colours of fireworks are produced by chemicals.  7 (a) Information about four chemicals is given in Table 2. Complete Table 2. **Table... show full transcript
Worked Solution & Example Answer:The colours of fireworks are produced by chemicals - AQA - GCSE Chemistry - Question 7 - 2014 - Paper 3
Step 1
Step 2
7 (b) Describe a test to show that barium chloride solution contains chloride ions.
Answer
To test for chloride ions, add a few drops of silver nitrate solution to the barium chloride solution.
Result: A white precipitate of silver chloride will form, indicating the presence of chloride ions.
Step 3
7 (c) Is the student's conclusion correct?
Answer
The student's conclusion is not correct. The blue precipitate formed when sodium hydroxide was added indicates the presence of copper ions (Cu²⁺), not iron(II) ions.
However, when the barium chloride was added to the solution containing sulfate ions, a white precipitate of barium sulfate would form, supporting that compound X contains sulfate ions. Thus, compound X is likely copper sulfate (CuSO₄) and not iron(II) sulfate.