Question

Consider a spontaneous electrochemical cell containing $Cd,C{d}^{2+},A{g}^{+}$, and $Ag$.
The reduction potential of $Cd$ is $-0.403V$ and $Ag$ is $0.799V$.

What is the balanced equation for the reaction that is occurring, and what is the electrochemical cell voltage?

• A. $A{g}^{+}+Cd\to C{d}^{2+}+Ag;1.19V$
• B. $2A{g}^{+}+Cd\to C{d}^{2+}+2Ag;1.20V$
• C. $A{g}^{+}+Cd\to C{d}^{2+}+A{g}^{+};0.40V$
• D. $2A{g}^{+}+Cd\to C{d}^{2+}+2Ag;2,30V$

Answer 1

The correct option is B $2A{g}^{+}+Cd\to C{d}^{2+}+2Ag;1.20V$

We have,

$E^0$ of Cd = -0.403V ( oxidation will favour)

$E^0$ of Ag = 0.799V (reduction will favour)

So, the net reaction becomes:

$2A{g}^{+}+Cd\to C{d}^{2+}+2Ag$

and $E_{cell}^0=0.799-(-0.403)=1.202V$