Question

Calculate the standard EMF ofa cell which involves the following cell reactions

\[\ce{Zn + 2 Ag+ -> Zn^{2+} + 2 Ag}\]

Given that \[\ce{E^{o}_{Zn/Zn^{2+}}}\] = 0.76 volt and \[\ce{E^{o}_{Ag/Ag^{+}}}\] = – 0.80 volt.

Options

• – 1.56 volts

• 1.56 volts

• – 0.04 volts

• 0.04 volts

Answer 1

1.56 volts

Explanation:

 \[\ce{E^{o}_{Zn/Zn^{2+}}}\] = 0.76 V or  \[\ce{E^{o}_{Zn^{2+}/Zn}}\] = – 0.76 V

\[\ce{E^{o}_{Ag/Ag^{+}}}\] = – 0.80 V or \[\ce{E^{o}_{Ag^+/Ag}}\] = + 0.80 V

\[\ce{E^{o}_{cell} = E^{o}_{cathode} - E^{o}_{anode}}\] = 0.80 – (– 0.76) = + 1.56 V