Question

Cell reaction is spontaneous when

• A. $E^0_{red}$ is negative
• B. $E^0_{red}$ is positive
• C. $ΔG^0$ is negative
• D. $ΔG^0$ is positive

Answer 1

Answer: (C)

$ΔG^0$ is negative

Answer 2

When the value of $ΔG^0$ is negative, the cell reaction is spontaneous.
$\, \, \, \, \, \, \, \, \, \, \, \, ΔG^0=-nFE^0$
where, n = number of electrons take part
F = Faraday constant $E^0=$ EMF of the cell
Thus, for a spontaneous reaction, the EMF of the cell must be positive.