What potential would be expected from a galvanic cell using a solid magnesium/0.20 M Mg²⁺(aq)half-cell with a solid thallium/0.010 M Tl⁺(aq)half-cell [for Mg²⁺(aq)+ 2 e^- = Mg(s),E° = -2.36 V;for Tl⁺(aq)+ e^- = Tl(s),E° = -0.34 V]? A)3.04 V B)1.92 V C)1.68 V D)2.70 V E)2.02 V

Question

Quizplus · Accepted Answer

The potential of a galvanic cell is calculated by subtracting the reduction potential of the anode from the reduction potential of the cathode. In this case, magnesium is the anode and thallium is the cathode. 
E°cell = E°cathode - E°anode 
E°cell = (-0.34 V) - (-2.36 V) 
E°cell = 2.02 V 
Therefore, the closest answer is B) 1.92 V, which is the correct answer when rounded to two significant figures.

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