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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. Figure 10 (a) Information about four chemicals is given in Table 2. Complete Table 2. Table 2 Chemical Colour... 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 dilute nitric acid to a sample of barium chloride solution, followed by a few drops of silver nitrate solution. If chloride ions are present, a white precipitate of silver chloride will form.
Step 3
7 (c) Is the student's conclusion correct?
Answer
The student's conclusion is not correct. The blue precipitate formed with sodium hydroxide indicates the presence of copper ions (Cu²⁺), not iron(II) ions. Moreover, the white precipitate formed when barium chloride was added indicates sulfate ions (SO₄²⁻) are present, which means that compound X could be copper sulfate (CuSO₄), not iron(II) sulfate.