Question

Consider a volatic cell based on these half -cell :
`Ag^(+) (aq.) + e^(-) rarr Ag(s), E^(@) = + 0.80 V`
`Cd^(2+) (aq) + 2e^(-) rarr Cd(s) , E^(@) = - 0.40 V`
Identify the anode and give the voltage of this cell under standard conditions
A. `Ag, E_("cell") = 0.40 V`
B. `Ag, E_("cell") = 2.00 V`
C. `Cd, E_("cell") = 1.20 V`
D. `Cd, E_("cell") = 2.00 V`

Answer 1

Correct Answer - C
Anode has lower standard reduction potential, thus Cd will be considered as anode
`E_("Cell")^(@) = E_("Cathode") - E_("Anode")`
`E_(Ag^(+) //Ag) - E_(Cd^(2+)//Cd)^(@)`
`= 0.80 - (-0.40) = 1.20 V`