Question

Write the Nernst equation for the cell reaction in the Daniel cell. How will the E_Cell be affected when concentration of Zn²⁺ ions is increased?

Answer 1

Daniell cell

\[\ce{Zn(s) | Zn^{2+} || Cu^{2+} | Cu(s)}\]

Anode: \[\ce{Zn(s) -> Zn^{2+} + 2e^{-}}\]

Cathode: \[\ce{Cu^{2+} + 2e^{-} -> Cu(s)}\]

Cell reaction: \[\ce{Zn(s) + Cu^{2+} <=>> Zn^{2+} + Cu(s)}\]

Q = `([Zn^{2+}])/([Cu^{2+}])`

`E_(Cell) = E_(Cell)^o - 0.059/2 log  ([Zn^{2+}])/([Cu^{2+}])`

Above equation shows that the cell potential will decrease with increase in the concentration of \[\ce{Zn^{2+}}\] ion.