The cell reaction of Daniel cell is $\mathrm{Zn}\left(\mathrm{s}\right)+{\mathrm{Cu}}^{2+}\left(\mathrm{aq}\right)⟶{\mathrm{Zn}}^{2+}\left(\mathrm{aq}\right)+\mathrm{Cu}\left(\mathrm{s}\right)$

The Nernst equation is ${\mathrm{E}}_{\text{cell }}={\mathrm{E}}_{\text{cell }}^{\circ }-\frac{0.059}{2}\log \frac{\left[{\mathrm{Zn}}^{2+}\right]}{\left[{\mathrm{Cu}}^{2+}\right]}$

E_cell decreases when the concentration of Zn²⁺ ions is increased as

i.     E_cell α concentration of Cu²⁺

ii.      E_cell is inversely dependent upon the concentration of Zn²⁺ ions.