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 solution of one salt tested with silver nitrate results in a yellow precipitate. This indicates that one of the possible anions is iodide, I⁻. Therefore, put a cross (X) in option C.
Step 2
Explain how the technician should do this.
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Answer
To determine which bottle contains the sodium salt and which contains the potassium salt, the technician should perform a flame test. The technician can take a small sample from each salt solution and place it in a non-luminous flame. Sodium salts will impart a bright yellow flame color, while potassium salts will produce a lilac flame. This color difference will help identify the respective salts.
Step 3
Describe what you would see when these solutions are mixed.
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Answer
When sodium hydroxide solution is mixed with a solution containing copper ions, a blue precipitate of copper(II) hydroxide, Cu(OH)₂, will form immediately. The solution will become cloudy and blue in color.
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(II) ions can be written as follows:
