Keeping in view the values of standard reduction potential given above, which one of the following would you select as a feasible redox chemical reaction?
Correct answer: C. Mg + 2H + -> Mg2+ + H2
- A. Cl- + I2 -> Cl2 + 2I-
- B. Cu + Zn2+ -> Cu2+ + Zn
- C. Mg + 2H + -> Mg2+ + H2
- D. 2Au + 6H+ -> 2Au3+ + 3 H2
Explanation
For a redox reaction to be feasible, the emf of it must be positive. (NOTE: When calculating emf, you take the voltage of each half equation according to the scenario, i.e. one will exhibit the same order as those shown above so, the E value is directly taken, but for some, you have to reverse the sign of the E value since the reaction, itself, is reversed). In option A, the emf is = -1.36 + 0.54 = -0.82, so NOT FEASIBLE. In option B, the emf is = -0.34 -0,76 = -1.10, so NOT FEASIBLE. In option C, the emf is = 2.37 + 0.00V = 2.37 so, it IS FEASIBLE; the answer is C. In option D, the emf is = -1.50 + 0 = -1.54 (the coefficient of the reaction is not taken into account) so, it is NOT FEASIBLE.
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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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