Testing for chlorides (Cl^-), bromides (Br^-) and iodides (I^-)
2 marks · NormalDescribe the steps you would take to test a solution for the presence of chloride, bromide, and iodide ions using silver nitrate.
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Add dilute nitric acid to the solution, then add silver nitrate solution.
Also accept: Acidify the solution with dilute nitric acid, then add silver nitrate solution.; Add a few drops of dilute nitric acid followed by silver nitrate solution.
Common mistakes: Adding hydrochloric acid instead of nitric acid.; Not stating the acidification step.; Adding silver nitrate before nitric acid.
Show mark scheme and worked solution
Marking points
M1 · 1 mark · States to add dilute nitric acid to the solution
M2 · 1 mark · States to add silver nitrate solution after acidifying
Worked solution
First, add a few drops of dilute nitric acid to the solution to acidify it.
Next, add silver nitrate solution to the acidified solution and observe the result.