Question

The standard emf of a galvanic cell involving $2$ moles of electrons in its redox reaction is $0.59V$. The equilibrium constant for the redox reaction of the cell is

• A. $10^{20}$
• B. $10^5$
• C. $10$
• D. $10^{10}$

Answer 1

Answer: (A)

In a galvanic cell, $\Delta G^{\circ }=-nF{E}^{\circ }$ ...(i)

Relationship between $\Delta G^{\circ }$ and equilibrium constant

$\Delta G^{\circ }=-2.303RT\log K_p$ ...(ii)

From Eqs. (i) and (ii), we get

$-2.303RT\log K_p=-nF{E}^{\circ }$

$\log K_p=\frac{nF{E}^{\circ }}{2.303RT}=\frac{n{E}^{\circ }}{\frac{2.303RT}{F}}$

$=\frac{2\times 0.59}{0.059}=20$

$K_p=AL(20)$ ( AL =Antilog)

$K_p=10^{20}$