A simple model for a concentration cell involving a metal `M` is
`M(s)|M^(o+)(aq,0.05 ` molar`)||M^(o+)(aq,1` molar`)|M(s)`
For the abov electrolytic cell, the magnitude of the cell potential is `|E_(cell)|=70mV.`
If the `0.05` molar solution of `M^(o+)` is replaced by a `0.0025` molar `M^(o+)` solution, then the magnitude of the cell potential would be
(a)`35mV`
(b)`70mV`
(c)`140mV`
(d)`700mV`

Options

A. 35mV
B. 70mV
C. 140mV
D. 700mV

Answer

C

Explanation

`M(s)|M^(+) (0.0025M)||M^(+) (1M)|M(s)`
`E_(cell) = 0 -(0.059)/(1)log _(10) ((0.0025)/(1)) =- (0.059)/(1) log _(10) 0.05^(2) = 2xx70 mV = 140 MV`