Question

Consider the following galvanic cell:

What happens to as the concentration of Zn²+ is increased? as the concentration of Ag+ is increased? What happens to E° in these cases?

Short answer

The effect has to be explained as concentration of metals are increased.

Step-by-step solution

Driving force of the reaction

The driving force of reaction called cell potential. It can be expressed as,

$\text{E}={\text{E}}^{\text{0}}-\text{RT}\ln \left(Q\right)$

Where, E is non-standard state of cell potential whereas E^o is standard state cell potential.

R is gas constant

T is temperature and Q is reaction quotient.

Half-cell reactions in galvanic cell

The half-cell reactions in given galvanic cell can be written as,

$\begin{array}{c}Zn\to Z{n}^{+2}+2e^{-}{E}^o=+0.76\\ A{g}^{+}{e}^{-}\to Ag{E}^o=0.8\end{array}$

The overall cell reaction can be written as,

role="math" $Zn+2A{g}^{+}\to 2Ag+Z{n}^{+2}$

Transfer of electrons during the reaction

The number of electron transferred in reaction$\left(n\right)=2,$

$E=E^o-\frac{0.0591}{2}log\left[\frac{Z{n}^{+2}}{A{g}^{+}}\right]$

E will be decreases when$\left[Z{n}^{2+}\right]$ increases whereas E increases when$\left[A{g}^{+}\right]$ increases due to the value of .$\left[\frac{Z{n}^{+2}}{A{g}^{+}}\right]$ The values same in cases and at standard conditions.