Question

A galvanic (voltaic) cell consists of an electrode composed of zinc in a 1.0 M zinc ion solution and another electrode composed of copper in a 1.0 M copper(II) ion solution, connected by a salt bridge. Calculate the standard potential for this cell at 25 °C. Standard reduction potentials can be found here.

Answer 1

Answer: The standard potential for the given cell is 0.89 V

Explanation:

The standard reduction potentials for zinc and copper are:

$E^o_{(Cu^{2+}/Cu)}=+0.13V\\E^o_{(Zn^{2+}/Zn)}=-0.76V$

The substance having highest positive $E^o$ potential will always get reduced and will undergo reduction reaction. Here, copper will undergo reduction reaction will get reduced.

Zinc will undergo oxidation reaction and will get oxidized.

Oxidation half reaction:  $Zn\rightarrow Zn^{2+}+2e^-$

Reduction half reaction:  $Cu^{2+}+2e^-\rightarrow Cu$

Oxidation reaction occurs at anode and reduction reaction occurs at cathode.

To calculate the $E^o_{cell}$ of the reaction, we use the equation:

$E^o_{cell}=E^o_{cathode}-E^o_{anode}$

Putting values in above equation, we get:

$E^o_{cell}=0.13-(-0.76)=0.89V$

Hence, the standard potential for the given cell is 0.89 V