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secondary 4 | Chemistry
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Why is B the answer?
Date Posted: 2 years ago
Views: 477
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This is a voltaic/galvanic/electrochemical cell. The zinc electrode is the anode which has (-) charge.
Electrons flow from it to the copper cathode which has a (+) charge.
Zinc and copper are both reactive electrodes. Zinc metal will be oxidised to zinc ions (Zn²+). However, there are few/no Cu²+ ions in the electrolyte of the lemon so no reduction of Cu²+ ions occur, and no copper metal will be deposited on the copper cathode. Some other ions in the organic acid present in the electrolyte will be reduced
A is correct.
B is not correct as the magnesium is a metal and a conductor of electricity. It can still receive electrons from the zinc anode (just that there is no reduction of Mg²+ ions since little/few Mg²+ ions exist in the electrolyte.) You will learn at A levels that the overall electrochemical cell potential is negative for such a combo (the reaction is spontaneous and circuit will flow)
C is correct (pretty obvious)
D is correct because oranges also contain organic acids (namely citric acid, and ascorbic acid i.e Vitamin C) and minerals.
Electrons flow from it to the copper cathode which has a (+) charge.
Zinc and copper are both reactive electrodes. Zinc metal will be oxidised to zinc ions (Zn²+). However, there are few/no Cu²+ ions in the electrolyte of the lemon so no reduction of Cu²+ ions occur, and no copper metal will be deposited on the copper cathode. Some other ions in the organic acid present in the electrolyte will be reduced
A is correct.
B is not correct as the magnesium is a metal and a conductor of electricity. It can still receive electrons from the zinc anode (just that there is no reduction of Mg²+ ions since little/few Mg²+ ions exist in the electrolyte.) You will learn at A levels that the overall electrochemical cell potential is negative for such a combo (the reaction is spontaneous and circuit will flow)
C is correct (pretty obvious)
D is correct because oranges also contain organic acids (namely citric acid, and ascorbic acid i.e Vitamin C) and minerals.
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