Consider an electrochemical cell based on the spontaneous reaction 2AgCl(s) + Zn(s) → 2Ag(s) + 2Cl– + Zn2+. If the zinc ion concentration is kept constant at 1 M, and the chlorine ion concentration is decreased from 1 M to 0.001 M, the cell voltage should:

there is an increase by 0.18 V in the cell voltage.

Explanation:

The given equation of the reaction can be well written as

By application of Nernst Equation ; we have the expression

here in the above equation;

n = number of electrons transferred in the equation of the reaction

n = 2

Also;

If the zinc ion concentration is kept constant at 1 M; we have:

Since log(1) = 0

Therefore;

When the chlorine ion concentration is decreased from 1 M to 0.001 M; we have;

The change in voltage =

=( 1.737 - 1.56 )V

= 0.177 V

≅ 0.18 V

Thus; from the following observation; there is an increase by 0.18 V in the cell voltage.