Question
Chlorine water is added to separate solutions of potassium bromide and potassium iodide. (a) Write a balanced symbol equation for the reaction with potassium bromide. (2) (b) State the colour change observed in the potassium iodide solution. (1) (c) Explain, in terms of electrons, why this is classified as a redox reaction. (2)
Mark scheme (5 marks):
(a) Cl₂(aq) + 2KBr(aq) → 2KCl(aq) + Br₂(aq) — correct formulae (1), correctly balanced (1).
(b) Colourless → brown / dark brown (iodine formed). (1)
(c) Chlorine gains electrons → reduced (1); bromide/iodide ions lose electrons → oxidised (1). Both processes occur together → redox.
5 marks · take your time before peeking.
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Generated by TopMyGrade AI · cross-check official sources before relying on the mark-scheme phrasing.