Question

The cell reaction of an electrolyte cell is given below:
$Fe+2F{e}^{3+}\to 3F{e}^{2+}$ with $E^o=0.404V$ and $\Delta G^o=-2.424kJ$. If the cell reaction is to be written as $2Fe+4F{e}^{3+}\to 6F{e}^{2+}$, then which of the following statements will be correct?

• A. $E^o$ will be given by $0.404V$.
• B. $\Delta G^o$ will be given by $-4.848kJ$.
• C. $\Delta G^o$ will be given by $-2.424kJ$.
• D. The value of $n$ changes from $6$ to $12$.

Answer 1

Answer: (A), (B), (D)

The correct options are
A $E^o$ will be given by $0.404V$.
B $\Delta G^o$ will be given by $-4.848kJ$.
D The value of $n$ changes from $6$ to $12$.

The cell reaction is written as $2Fe+2F{e}^3\to 6F{e}^{2+}$.

$\left(A\right)$ If the cell reaction is multiplied by $2$, the value of the cell potential remains the same. It is not multiplied by $2$.
Hence, the cell potential will be $0.404V$.
Thus, option A is correct.

$\left(B\right)$ If the cell reaction is multiplied by $2$, the value of the free energy change is also multiplied by $2$ as the number of electrons that takes part in the cell reaction is multiplied by $2$.
Hence, the value of the standard free energy change will be $2\times 2.424kJ=-4.848kJ$
Thus, option B is correct.

$\left(C\right)$ The option C is not correct as the standard free energy change is $-4.848kJ$.

$\left(D\right)$ When the cell reaction is multiplied by $2$, the number of electrons are also multiplied by $2$.
The value of $n$ changes from $6$ to $12$.
Hence, option D is correct.

Hence, options A, B, and D are correct.