Photo AI
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.  (a) Information about four chemicals is given in Table 2. Complete Table 2. Table 2 | Chemica... 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
Describe a test to show that barium chloride solution contains chloride ions. Give the result of the test.
Answer
To test for the presence of chloride ions, add a few drops of silver nitrate solution to the barium chloride solution. If chloride ions are present, a white precipitate of silver chloride will form as the result of the reaction:
ightarrow ext{AgCl} (s) $$.Step 3
Is the student’s conclusion correct? Explain your answer.
Answer
The student's conclusion is incorrect. The formation of a blue precipitate with sodium hydroxide indicates the presence of copper ions, not iron(II) ions. Copper(II) ions react with sodium hydroxide to form a blue precipitate:
ightarrow ext{Cu(OH)}_2 (s) $$. Additionally, the formation of a white precipitate when barium chloride is added suggests that sulfate ions are present, confirming that compound X is likely copper sulfate (CuSO4), not iron(II) sulfate.