The electrolysis of other molten substances
4 marks · NormalThis question is about the electrolysis of molten lead(II) bromide.
Write the balanced ionic half-equation for the reaction at the cathode.
Write the balanced ionic half-equation for the reaction at the anode.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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(a) Pb^{2+} + 2e^- \to Pb
(b) 2Br^- \to Br_2 + 2e^-
Common mistakes: Unbalanced equations; Electrons on wrong side
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Marking points
M1 (a) · 1 mark · Writes half-equation with ions and electrons present for cathode
A1 (a) · 1 mark · Correctly balances both atoms and charges for cathode equation
M2 (b) · 1 mark · Writes half-equation with ions and electrons present for anode
A2 (b) · 1 mark · Correctly balances both atoms and charges for anode equation
Worked solution
a) Cathode (reduction):
b) Anode (oxidation):