Question

For the feasibility of a redox reaction in a cell, its e.m.f. should be

• A. Positive
• B. Fixed
• C. Zero
• D. Negative

Answer 1

Answer: (A)

Any redox reaction would occur spontaneously if the free energy change $(\Delta G)$ is negative. $\Delta G^o=-nF{E}^o$

Where $n$ is the number of electrons involved, $F$ is the value of Faraday and $E^o$ is the cell emf. $\Delta G^o$ can be negative if $E^o$ is positive.