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Electrochemistry

Question
CBSEENCH12006137

Calculate the Δr G° and the equilibrium constant for the reaction
2Cr(s) + 3Cd2+ (aq) 2Cr3+ (aq) + 3Cd(s)
(Given E°Cr3+/Cr = 0.74 V, E°Cd2+/ Cd = – 0.40 V)

Solution

            E°cell = E°Cd2+/Cd - E°Cr3+/Cr          = - 0.40 - (0.74) = +0.34 V
∴         rG° = -nFE° = -6 × 96500 × 0.34 = -196860 J     K = Antilog nE°0.059 = Antilog6×0.340.059          = Antilog (34.5762)  K = 3.77 × 1034.