The standard reduction potential of Zn and Ag in water at 298 K are,
`Zn^(2+)+2e^(-)toZn,E^@` =-0.76 V and
`Ag^++e^(-)toAg,E^@` =+0.80 V
Which of the following reactions takes place?

Options

A. `Zn_((aq))^(2+)+Ag_((aq))^(+)toZn_((aq))+Ag_((s))`
B. `Zn_((s))+Ag_((aq))toZn_((aq))^(2+)+Ag_((aq))^(+)`
C. `Zn_((aq))^(2+)+2Ag_((s))to2Ag_((aq))^(+)+Zn_((s))`
D. `Zn_((s))+2Ag_((aq))^(+)toZn_((aq))^(2+)+2Ag_((s))`

Answer

D

Explanation

The values of standard reduction potential of Zn and Ag suggest that Zn would undergo oxidation (lower reduction potential) and Ag would undergo reduction (higher reduction potential). So the cell reaction must be
`\Zn+2Ag^(+)toZn^(2+)+2Ag`