KCET2013ChemistryElectrochemistry
The emf of a galvanic cell constituted with the electrodes Zn ²⁺ Zn (-0.76 ~V ) and Fe ²⁺ Fe (-0.41 ~V ) is
Options
- A-0.35 ~V
- B+1.17 ~V
- C+0.35 ~V
- D-1.17 ~V
Correct answer
C. +0.35 ~V
Step-by-step solution
The cell reaction may be split into two half reactions as aligned & Zn ²⁺+2 e ⁻ Zn ; E_ red ^ =-0.76 ~V & Fe ²⁺+2 e ⁻ Fe ; E_ red ^ =-0.44 ~V aligned As Zn ²⁺ ion has lower reduction potential than Fe ²⁺ ion. Thus, oxidation takes place on zinc electrode standard EMF of the cell = [ array l Standard reduction potential of the the reduction half reaction array ]- [ array l Standard reduction potential of the oxidation half reaction array ]=-0.44-(-0.76)=+0.35 ~V