Question

Predict the potential for the following voltaic cell at 25 C: Cu(s)|CuSO4(0.42 M)||AgNO3(0.46 M)|Ag(s) (answer in volts)

Answer 1

Cu(s)|CuSO4(0.42 M)||AgNO3(0.46 M)|Ag(s)

anode reaction: oxidation takes place

Cu(s) -------------------------> Cu+2 (aq) + 2e-   ,   E⁰_Cu+2/Cu = + 0.34 V

cathode reaction : reduction takes palce

Ag+(aq) + e- -----------------------------> Ag(s) , E⁰ =   + 0.80 V

--------------------------------------------------------------------------------

net reaction: Cu(s) + 2 Ag+(aq) -------------------------> Cu+2 (aq) + Ag(s)

E⁰_cell= E⁰_cathode- E⁰_anode

E⁰_cell = 0.80 - 0.34

          = 0.46 V

nernest equation

Ecell = E⁰_cell -(0.0591/n)* log [Cu+2]/[Ag+]^2

Ecell = 0.46 - (0.059 x1/2) *log 0.42/0.46^2}

Ecell   = 0.45 V

cell potential =Ecell   = 0.45 V