NEETChemistryElectrochemistryMCQ+4 / −1
EoFe2+/Fe = 0.441 V and EoFe3+/Fe2+ = 0.771 V, the standard EMF of the reaction Fe + 2Fe3+ 3Fe2+ will be
- A0.111 V
- B0.330 V
- C1.653 V
- D1.212 V
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Correct answer: D
At anode : Fe Fe2+ + 2e-; Eo = -0.441 V
At cathode : Fe3+ + e– Fe2+; Eo = 0.771 V
Fe + 2Fe3+ 3Fe2+; Eo = ?
To get the above equation, (ii) × 2 – (i)
2Fe3+ + 2e– 2Fe2+; Eo = 0.771 V
Fe Fe2+ + 2e-; Eo = - 0.441 V
------------------------------------------------
Fe + 2Fe3+ 3Fe2+
Eo = 0.771 + 0.441 = 1.212 V
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