Testing for chlorides (Cl^-), bromides (Br^-) and iodides (I^-)
4 marks · NormalState the expected observation if chloride ions are present when silver nitrate solution is added after acidifying.
State the expected observation if bromide ions are present when silver nitrate solution is added after acidifying.
State the expected observation if iodide ions are present when silver nitrate solution is added after acidifying.
A student tested a solution using dilute nitric acid and silver nitrate. The result was a cream precipitate. Which ion is present?
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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(a) A white precipitate forms · must show white precipitate
(b) A cream precipitate forms · must show cream precipitate
(c) A yellow precipitate forms · must show yellow precipitate
(d) Bromide ions, Br^- · must show Br^-, bromide
Show mark scheme and worked solution
Marking points
A1 (a) · 1 mark · White precipitate for chloride
A2 (b) · 1 mark · Cream precipitate for bromide
A3 (c) · 1 mark · Yellow precipitate for iodide
A4 (d) · 1 mark · Br^- or 'bromide' correctly identified
Worked solution
(a) Chloride ions give a white precipitate.
(b) Bromide ions give a cream precipitate.
(c) Iodide ions give a yellow precipitate.
(d) A cream precipitate indicates bromide ions (Br^-).