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What is observed when concentrated hydrochloric acid is added to an aqueous solution of CuSO₄ until no further change occurs? A colourless gas is evolved and a precipitate forms - AQA - A-Level Chemistry - Question 18 - 2019 - Paper 3
Question 18
What is observed when concentrated hydrochloric acid is added to an aqueous solution of CuSO₄ until no further change occurs? A colourless gas is evolved and a prec... show full transcript
Worked Solution & Example Answer:What is observed when concentrated hydrochloric acid is added to an aqueous solution of CuSO₄ until no further change occurs? A colourless gas is evolved and a precipitate forms - AQA - A-Level Chemistry - Question 18 - 2019 - Paper 3
Step 1
D The solution changes colour and no precipitate forms.
Answer
When concentrated hydrochloric acid is added to an aqueous solution of copper(II) sulfate (CuSO₄), a chemical reaction occurs that leads to a color change in the solution. The presence of chloride ions from the hydrochloric acid interacts with the copper ions, resulting in the formation of copper(II) chloride, which gives the solution a different color.
It is important to note that no precipitate forms during this reaction as copper(II) sulfate remains soluble in concentrated hydrochloric acid, and its characteristic blue color transforms to a more greenish hue.
Thus, the correct observation is that the solution changes colour and no precipitate forms.