Question

Calculate the cell potential for the following reaction that takes place in an electrochemical cell at 25

Answer 1

Sn²⁺(aq) + 2(e^-) --------> Sn(s) ; E⁰_cell = -0.14 V

Ag⁺(aq) + (e^-) --------> Ag(s)  ; E⁰_cell = 0.80 V

thus, for the cell , Sn(s) | Sn2+(aq, 0.022 M) || Ag+(aq, 2.7 M) | Ag(s)

the overall reaction is :-

2Ag⁺(aq) +  Sn(s) -----------> 2Ag(s) + Sn²⁺(aq) ;  E⁰_cell = 0.80 - (-0.14) = 0.94 V

now, as per Nernst equation:

E_cell =  E⁰_cell - (0.0591/n)*log{[ Sn²⁺]/[Ag⁺]²}; where n = number of electron transfer taking place

or, E_cell = 0.94 - (0.0591/2)*log{0.022/(2.7)²} = 1.0145 V