A technician had two bottles containing solid salts - Edexcel - GCSE Chemistry - Question 2 - 2015 - Paper 1
Question 2
A technician had two bottles containing solid salts.
One bottle contained a potassium salt and the other contained a sodium salt.
Unfortunately the labels had fallen... show full transcript
Worked Solution & Example Answer:A technician had two bottles containing solid salts - Edexcel - GCSE Chemistry - Question 2 - 2015 - Paper 1
Step 1
Complete the sentence by putting a cross (X) in the box next to your answer.
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Answer
The test shows that the anion in the salt is C iodide, I⁻. This is indicated by the yellow precipitate formed with silver nitrate, which confirms the presence of iodide ions.
Step 2
Explain how the technician should do this.
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Answer
The technician can identify which salt is sodium and which is potassium by performing a flame test. When heated in a flame, sodium will produce a bright yellow color, while potassium will yield a lilac or pale violet color. By comparing the colors of the flame produced by each salt, the technician can determine which is which.
Step 3
Describe what you would see when these solutions are mixed.
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Answer
When sodium hydroxide is mixed with a solution containing copper ions, a blue precipitate of copper hydroxide, Cu(OH)₂, will form. Initially, a pale blue solution will be observed, which then turns cloudy as the precipitate settles out.
Step 4
Write the ionic equation for this reaction.
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Answer
The ionic equation for the reaction between sodium hydroxide and copper ions is given by:
