Question

7) Write nearest equation for the cell reaction in the Daniel cell. How will the ecell be affected when concentration for zn²⁺ ions is increased?

Answer 1

Dear Student


The Nernst Equation for the Cell Reaction in the Daniel Cell -

Zn(s) ​| Zn²⁺ $\parallel$ Cu²⁺ | Cu (s)

Now, reactions taking place at the two electrodes -

Anode - ​Zn(s) $\to$Zn²⁺ + 2e^-

Cathode - ​ Cu²⁺ + 2e^- $\to$ Cu (s)

Therefore,

Cell Reaction - ​Zn(s)​ + Cu²⁺ + 2e^- $\leftrightarrow$Zn²⁺ + 2e^- + Cu (s)​

OR, ​Zn(s)​ + Cu²⁺$\leftrightarrow$Zn²⁺ + Cu (s)​​


Now, Q = $\frac{\left[Z{n}^{2+}\right]}{\left[C{u}^{2+}\right]}$
And, E_cell = E^o_cell - $\frac{0.059}{2}\log$ $\frac{\left[Z{n}^{2+}\right]}{\left[C{u}^{2+}\right]}$
Hence, we can say, the increase in the concentration of Zn²⁺ will decrease the Cell Potential.


Regards