Question

The emf of the cell involving the following reaction ${2Ag^+ + H_2 -> 2Ag + 2H^+}$ 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)

$0.80 \,V$

Answer 2

$2Ag^+ + H_2 {->} 2Ag + 2H^+$
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,
$E^{\circ}_{Ag/Ag^+} = -0.80\,V$