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Calculate the standard electrode potential E o for F e + + + + e - → F e + + From the given standard electrode potentials value of two half cells F e + + + 2 e - → F e ; E o = - 0.440 V F e + + + + 3 e - → F e ; E o = - 0.036 V

Options

  1. A+ 0 .772   V
  2. B– 0 .404   V
  3. C+ 0 .404   V
  4. D– 0 .476   V

Correct answer

A. + 0 .772   V

Step-by-step solution

Δ G o = - n E o F F e 2 + + 2 e - → F e .....(i) Δ G o = - 2 × F × ( - 0.440 V ) = 0.880 F F e 3 + + 3 e - → F e .....(ii) ΔG o = − 3 × F × − 0 .036 = 0 .108   F On subtracting equation (i) from (ii) F e 3 + + e - → F e 2 + ΔG o = 0 .108   F − 0 .880   F = − 0 .772   F E o for the reaction = - Δ G o n F = - ( - 0.772 F ) 1 × F =+ 0.772 V

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