Which of the following reactions occur at cathode?
Correct answer: A. Cu2++ 2e- → Cu
- A. Cu2++ 2e- → Cu
- B. Cu + 2e- → Cu2+
- C. Hg + 1/2O2 → HgO
- D. Mg + 1/2O2 → MgO
Explanation
Option A is correct.The reaction that occurs at the cathode is the reduction reaction. In a reduction reaction, electrons are gained by an atom or ion. The reactions that you have listed are: Cu2+ + 2e- → Cu The reaction is a reduction reaction. In this reaction, copper ions gain 2 electrons to form copper metal. The other reactions are oxidation reactions, in which electrons are lost by an atom or ion. Therefore, the reaction that occurs at the cathode is Cu2+ + 2e- → Cu.
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Electrochemistry describes electron transfer through oxidation and reduction, identifies oxidizing and reducing agents, and applies oxidation numbers to balance redox equations. It also covers electrode potential and the standard hydrogen electrode, which provides the reference for comparing the reduction tendencies of other electrodes.
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