Question

The standard cell potential (E°cell) for the reaction below is +1.10V. The cell potential for this reaction is ________ V when the concentration of [Cu2+]=1.0⋅10−5M and [Zn2+]=2.5M. Zn (s) + Cu2+ (aq) → Cu (s) + Zn2+ (aq) The standard cell potential () for the reaction below is . The cell potential for this reaction is ________ when the concentration of and (s) + (aq) (s) + (aq) 0.78 1.10 0.94 1.26 1.42

Answer 1

Answer: 0.94 V

Explanation:

For the given chemical reaction :

$Zn(s)+Cu^{2+}(aq)\rightarrow Cu(s)+Zn^{2+}$

Using Nernst equation :

$E_{cell}=E^o_{cell}-\frac{2.303RT}{nF}\log \frac{[Zn^{2+}]}{[Cu^{2+}]}$

where,

F = Faraday constant = 96500 C

R = gas constant = 8.314 J/mol.K

T = room temperature = $298K$

n = number of electrons in oxidation-reduction reaction = 2

$E^o_{cell}$ = standard electrode potential of the cell = +1.10 V

$E_{cell}$ = emf of the cell = ?

Now put all the given values in the above equation, we get:

$E_{cell}=+1.10-\frac{2.303\times (8.314)\times (298)}{2\times 96500}\log \frac{2.5}{1.0\times 10^{-5}}$

$E_{cell}=+1.10-0.16V=0.94V$

The cell potential for this reaction is 0.94 V