Question

$Zn\left(s\right)+C{l}_2(1$ atm$)\to Z{n}^{2+}+2C{l}^{-}:E^o=2.12V$ . To increase the e.m.f. of the above cell:

• A. $\left[Z{n}^{2+}\right]$ should be increased
• B. $\left[Z{n}^{2+}\right]$ should be decreased
• C. $\left[C{l}^{-}\right]$ should be increased
• D. $PC{l}_2$ should be decreased

Answer 1

The correct option is B $\left[Z{n}^{2+}\right]$ should be decreased

To increase the e.m.f. of the above cell $\left[Z{n}^{2+}\right]$ should be decreased.
With decrease in the concentration of zinc ions, the equilibrium will shit in the forward direction which will increase the cell potential.
$E=E^o-\frac{0.059}{2}log\frac{\left[Z{n}^{2+}\right][C{l}^{-}{]}^2}{P_{C{l}_2}}$