For the cell reaction, `Mg(s)+2Ag^(+) (aq.) rarr Mg^(2+) (aq) + 2Ag(s) E_(cell)^(@)` : +3.17 V at 298 K. The value of `E_(cell)^(@) triangle G^(@)` and at `Ag^(+)` and `Mg^(2+)` concentrations of 0.001 M and 0.02 M respectively are:

Options

A. `3.04V, -605.8kJ mol^(-1), 20000`
B. `3.04V, 611.8kJ mol^(-1), 20000`
C. `3.13V, -604kJ mol^(-1), 20`
D. `3.04V, -611.8kJ mol^(-1), 20000`

Answer

D

Explanation

`E^(@) = +3.17V, n=2`
`Q= ([Mg^(2+)])/([Ag^(+)]^(2))= (0.02)/([0.001]^(2))= 20000`
`Delta G^(@)= -nFE^(@)= -2 xx 96500 xx 3.17 = -611.8kJ`
`E= E^(@) - (0.059)/(n) log_(10) Q= 3.17- (0.059)/(2) log (20000) = +3.04V`