Testing for chlorides (Cl^-), bromides (Br^-) and iodides (I^-)

2 marks · Normal

Describe the steps you would take to test a solution for the presence of chloride, bromide, and iodide ions using silver nitrate.

Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.

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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.