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A student adds a few drops of sodium hydroxide solution to an unknown solution and a blue precipitate is made - OCR Gateway - GCSE Chemistry - Question 2 - 2020 - Paper 1
Question 2
A student adds a few drops of sodium hydroxide solution to an unknown solution and a blue precipitate is made. Which metal ion is present in the original solution? ... show full transcript
Worked Solution & Example Answer:A student adds a few drops of sodium hydroxide solution to an unknown solution and a blue precipitate is made - OCR Gateway - GCSE Chemistry - Question 2 - 2020 - Paper 1
Step 1
Which metal ion is present in the original solution?
Answer
When sodium hydroxide (NaOH) is added to a solution containing metal ions, a blue precipitate indicates the presence of Copper(II) ions (Cu²⁺). The formation of this blue precipitate is a characteristic reaction, as copper hydroxide (Cu(OH)₂) is insoluble in water and appears as a blue solid. Therefore, the correct answer is: B. Copper(II).