Question

The button cell used in watches functions as follows.

\[\ce{Zn_{(s)} + Ag2O_{(s)} + H2O_{(l)} ⇌ 2Ag_{(s)} + Zn^{2+}_{( aq)} + 2OH^-_{( aq)}}\] the half cell potentials are \[\ce{Ag2O_{(s)} + H2O_{(l)} + 2e^- -> 2Ag_{(s)} + 2OH^-_{( aq)}}\] E⁰ = 0.34 V The cell potential will be

Options

• 0.84 V

• 1.34 V

• 1.10 V

• 0.42 V

Answer 1

1.10 V

Explanation:

Anodic oxidation: (Reverse the given reaction)

\[\ce{(E^0_{ox})}\] = 0 76. cathodic reduction

∴ \[\ce{E^0_{cell} = (E^0_{ox}) + (E^0_{red})}\]

= 0.76 + 0.34

= 1.1 V