CAIE A Level Chemistry 9701 · Group 17
A student adds aqueous solutions of chlorine, bromine and iodine separately to aqueous potassium iodide, aqueous potassium bromide and aqueous potassium chloride. The student records whether a reaction occurs and the colour of the solution after mixing.
Describe how the results of this experiment show the relative reactivity of the halogens as oxidising agents.
5 marks, so the mark scheme is looking for about 5 separate creditworthy points. Making the same point twice in different words earns it once.
Describe means: Say what happens or what something is like, in order and with detail. You are not being asked why. If there is data, quote it: name the trend, then give figures with units at the points where it changes.
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