The EMF of the standard weston cadmium cell

Cd (12.5%) in Hg | 3 CdSO₄, 8H₂O (solid) | standard solution of CdSO₄ | Hg₂SO₄ (s) | Hg is 1.0180 volts at 25°C and the temperature coefficient of the cell emf, \(\left(\frac{\delta E}{\delta T}\right)_P\) = \(-4.0 × 10^{-5}\text{ V deg}^{-1}\). Calculate \(\Delta G\), \(\Delta H\) and \(\Delta S\) for the reaction in the cell when n = 2.

\(\Delta G\) = –196.5 kJ, \(\Delta H\) = 198.8 kJ, \(\Delta S\) = –7.72 J/deg

Given,

\(\left(\frac{\delta E}{\delta T}\right)_P\) = \(-4.0 x 10^{-5}\text{ V deg}^{-1}\)

\(n = 2\)

\(E^0_{cell} = 1.0181V\)

We know,

\(\Delta G^0 = −2FE^0_{cell}\)

or, \(\Delta G^0 = −2 × 96500 × 1.018\)

or, \(\Delta G^0 = −196474 J\)

or, \(\Delta G^0 = −196.5 kJ\)

\(\Delta S^0  = nF\left(\frac{dE}{dT}\right)\)

or, \(\Delta S^0 = −2 × 96500 × 4.0 × 10^{-5}\)

or, \(\Delta S^0 = −7.72 J/deg\)

\(\Delta H^0 =nF\left(T\left(\frac{dE}{dT}\right)_P − E^0_{cell} \right) = 198.8 kJ\)