Question

The standard potentials for and half reaction are $- 0.136V$ and $- 0.440V$ respectively. At what relative concentration of $S{n^{2 + }}$ and $F{e^{3 + }}$ will these have the same reduction potential?

Answer 1

Standard potential : they are the physical quantities that represent essential properties of the system that evolve metals and gases on one hand and ions in the solution on the other. ${E^o} =$ ${E^o}$ of cathode-${E^o}$of cathode Further,this can be used in the nernst equation:
Which states that ${E^o} = \dfrac{{2.303RT}}{{nF}}\log {K_C}$.

Complete step-by-step answer: Standard potential : they are the physical quantities that represent essential properties of the system that evolve metals and gases on one hand and ions in the solution on the other.
Reduction potential:reduction potential is the measure of the tendency of a chemical species to acquire or lose electrons and form reduction and oxidation potential respectively.
Then we should apply the following formulas:
${E^o} =$ ${E^o}$ of cathode-${E^o}$of cathode
Further,this can be used in the nernst equation:
Which states that ${E^o} = \dfrac{{2.303RT}}{{nF}}\log {K_C}$
Where the value of ${K_C}$ determines the extent of the cell reaction. This reaction takes place at equilibrium or when the reaction is about to attain equilibrium.

Note: Thus we can say that the above equation gives a relationship between equilibrium constant of the reaction and the standard potential of the cell in which that reaction takes place. Thus, equilibrium constant of the reaction is difficult to measure.