Electrolysis and redox
3 marks · EasyDuring the electrolysis of molten copper(II) bromide (CuBr), the following reactions occur:
Write the half-equation for the reaction at the anode.
State whether the anode reaction is oxidation or reduction.
Explain your answer to (b) using electron transfer.
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) \ce{2Br^- -> Br2 + 2e^-}
(b) Oxidation
(c) Because bromide ions lose electrons at the anode.
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Marking points
B1 (a) · 1 mark · Writes correct half-equation: 2Br \rightarrow Br + 2e.
B1 (b) · 1 mark · States oxidation.
M1 (c) · 1 mark · Explains oxidation is loss of electrons (bromide ions lose electrons at anode).
Worked solution
a) The half-equation is: 2Br \rightarrow Br + 2e
b) This reaction is oxidation.
c) Because bromide ions lose electrons at the anode (oxidation is loss of electrons).