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3.4 Electrolysis

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Question 2

A teacher is planning four electrolysis demonstrations. Each one will use an aqueous solution and graphite electrodes.

The relevant part of the reactivity series is shown, with the most reactive metal first:

potassium, magnesium, zinc, (hydrogen), copper

The planned demonstrations are:

  • Cell P must produce hydrogen at the negative electrode and chlorine at the positive electrode. Magnesium chloride solution will be used.
  • Cell Q must produce copper at the negative electrode and oxygen at the positive electrode. Copper(II) nitrate solution will be used.
  • Cell R must produce zinc at the negative electrode and iodine at the positive electrode. Zinc iodide solution will be used.
  • Cell S must produce potassium at the negative electrode and sulfur at the positive electrode. Potassium sulfate solution will be used.

Evaluate whether the solution chosen for each cell will produce both of the required products.

For any cell that will not produce the required products, give the products that will form instead. Explain your decisions using the ions present in aqueous solutions.

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Markscheme

3.4 Electrolysis Questions

  1. GCSE
  2. /Chemistry
  3. /3.4 Electrolysis

98 exam-style questions on OCR GCSE Chemistry 3.4 Electrolysis, covering 3.4.1 Products formed at the electrodes in electrolysis and 3.4.2 The technique of electrolysis. Each one has a worked solution and a mark scheme showing where the marks go.

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