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AQA · GCSE · Chemistry · Higher

Aluminium reduction half equation

Q06.5 2 marks

Figure 10 shows the electrolysis cell used to extract aluminium from aluminium oxide.

Figure 10
Figure 10

Figure 10

Enlarged question image

Figure 10

The formula of aluminium oxide is Al₂O₃.

Write a half equation for the reaction at the negative electrode in Figure 10.

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Marking points

  1. 1 Places Al³⁺, electrons and Al in the correct printed positions.
  2. 2 Uses three electrons to balance charge.

Why this answer loses marks

I used the right aluminium species but did not balance the charge.

The species can earn partial credit, but the electron coefficient must make the total charge equal on both sides.