Q. For the given cell $\text{Fe}^{2+}_{(aq)}+\text{Ag}^+_{(aq)}\to\text{Fe}^{3+}_{(aq)}+\text{Ag}_{(s)}$ The standard cell potential of the reaction is. Given: $\text{Ag}^++e^-\to\text{Ag}$ $E^\theta=xV$; $\text{Fe}^{2+}+2e^-\to\text{Fe}$ $E^\theta=yV$; $\text{Fe}^{3+}+3e^-\to\text{Fe}$ $E^\theta=zV$
A) $x+y-z$
B) $x+2y$
C) $x+2y-3z$
D) $y-2x$
Explanation
[Solution by Dr. Abubacker] $\text{Fe}^{3+}+e^-\to\text{Fe}^{2+}$: $\Delta G=-3zF-(-2yF)$ so $E^\theta_{\text{Fe}^{3+}/\text{Fe}^{2+}}=3z-2y$. Cell reaction: $E^\theta_{cell}=E^\theta_{\text{Ag}^+/\text{Ag}}-E^\theta_{\text{Fe}^{3+}/\text{Fe}^{2+}}=x-(3z-2y)=x+2y-3z$. Answer (3).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.