An analytical chemist is testing a sample of reservoir water to determine if it contains chloride ions.
The chemist designs the following procedure:
Step 1 Transfer a 10 cm3 sample of the reservoir water into a clean test tube. Step 2 Add a few drops of dilute hydrochloric acid. Step 3 Add a few drops of silver nitrate solution. Step 4 Observe whether or not a precipitate forms.
This procedure will not provide a valid test for chloride ions.
Explain the change that must be made to Step 2, and why this change is necessary, to allow the test to work.
Practise Edexcel GCSE Chemistry Qualitative analysis: tests for ions with exam-style questions for Foundation and Higher tier. 127 questions, matched to the Edexcel GCSE Chemistry (1CH0) specification and written in Paper 1 and Paper 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.
