Question

Any redox reaction would occur spontaneously, if :

• A. The free energy change $\left(\Delta G\right)$ is negative
• B. The $\left(\Delta G\right)$ is positive
• C. The cell e.m.f. $\left(E\right)$ is negative
• D. All of these

Answer 1

The correct option is A The free energy change $\left(\Delta G\right)$ is negative

For a reaction to be spontaneous, $\Delta$G should be negative.
As we know,
$\Delta G$ = $–nFE$
If $E_{cell}=+ve$
$⟹\Delta G=–ve$ and reaction is spontaneous.
Thus, reaction is spontaneous when the free energy change $\left(\Delta G\right)$ is negative and $E_{cell}$ is positive.