Question

The emf of the cell involving the following reaction
$ 2Ag^+ + H_2 \rightarrow 2Ag + 2H^+ $
is $ 0.80 \,Volt $ . The standard oxidation potential of silver electrode is

• A. -0.80 V
• B. 0.80 V
• C. 0.40 V
• D. -0.40 V

Answer 1

Answer: (B)

$2Ag^+ + H_2 \rightarrow 2Ag + 2H^+$
By convention, the cell may be represented as.
$H_2 |H^+|Ag^+|Ag$
$\therefore E^{\circ}_{\text{cell}} = E^{\circ}_{Ag^+/Ag} -E^{\circ}_{H^+/H_2}$
or $E^{\circ}_{Ag^+/Ag} = E^{\circ}_{\text{cell}} + E^{\circ}_{H^+/H_2}$
$ = 0.80 + 0 = 0.80\,v$
Thus, standard reduction potential of $Ag$ electrode as,
$E^{\circ}_{Ag^+/Ag} = 0.80\,V$
and standard oxidation potential of $Ag$ electrode as,
$E^{\circ}_{Ag/Ag^+} = -0.80\,V$