CAIE A Level Chemistry 9701 · Group 17
A colourless solution contains one halide ion. A student adds aqueous silver nitrate and observes a cream precipitate. Addition of dilute aqueous ammonia does not dissolve the precipitate, but addition of concentrated aqueous ammonia does dissolve it. Suggest which halide ion is present and explain your reasoning.
4 marks, so the mark scheme is looking for about 4 separate creditworthy points. Making the same point twice in different words earns it once.
Suggest means: Apply what you know to an unfamiliar situation. There may be more than one acceptable answer. Reason from the principle you have learned to the new context, and say which principle you are using.
Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.