JEE Main202523 Jan 2025Evening ShiftChemistryElectrochemistryActual
Standard electrode potentials for a few half cells are mentioned below : aligned & E _ Cu ²⁺ / Cu ^ =0.34 ~V , E _ Zn ²⁺ / Zn ^ =-0.76 ~V & E _ Ag ⁺ / Ag ^ =0.80 ~V , E _ Mg ²⁺ / Mg ^ =-2.37 ~V aligned Which one of the following cells gives the most negative value of G ^ ?
Options
- AZn | Zn ²⁺(1 M ) | | Ag ⁺(1 M ) | Ag
- BZn | Zn ²⁺(1 M ) | | Mg ²⁺(1 M ) | Mg
- CAg | Ag ⁺(1 M ) | | Mg ²⁺(1 M ) | Mg
- DCu | Cu ²⁺(1 M ) | Ag ⁺(1 M ) | Ag
Correct answer
A. Zn | Zn ²⁺(1 M ) | | Ag ⁺(1 M ) | Ag
Step-by-step solution
gathered G ^ =- nFE ^ Option (1) E ^ =0.8+0.76 =1.56 ~V G ^ =-2 F 1.56 =-3.12 ~V Option (2) E ^ =-2.37+0.76 =-1.61 ~V G ^ =-2 F (-1.61) =+3.22 ~V Option (3) E ^ =-2.37-0.8 =-3.17 ~V . array c G ^ =-2 array ) F (-3.17) =+6.34 Option (4) E ^ =0.8-0.34 =0.46 ~V G ^ =-2 F 0.46 =-0.92 ~V gathered