The standard emf of the cell, `Cd(s) |CdCI_(2) (aq) (0.1M)||AgCI(s)|Ag(s)` in which the cell reaction is `Cd(s) +2AgCI(s) rarr 2Ag(s) +Cd^(2+) (aq)` is `0.6915 V` at `0^(@)C` and `0.6753V` at `25^(@)C`. The `DeltaH` of the reaction at `25^(@)C` is,-

Options

A. `-176 kJ`
B. `-234.7 kJ`
C. `+123.5 kJ`
D. `-167.26 kJ`

Answer

D

Explanation

`DeltaG =- nFE^(@) = DeltaH^(@) - T DeltaS^(@)`
`=-2 F xx 0.695 = DeltaH^(@) - 273 DeltaS^(@)` ...(i)
`=- 2F xx 0.6753 = DeltaH^(@) - 298 DeltaS` ..(ii)
Solve both equation.