Question

The temperature coefficient of the emf i.e., $\frac{\text{dE}}{\text{dt}} = - 0.00065 \text{ VK}^{- 1} \, $ for the cell $Cd\left|\right.CdCl_{2}\left(1 M\right)\left|\right.\left|\right.AgCl\left(s\right)\left|\right.Ag$ at $\text{25}^{\text{o}} \text{C}$ . Calculate the entropy changes $\text{ΔS} \, \text{298} \, \text{K}$ for the cell reaction $\text{Cd} + \text{2} \, \text{AgCl} \rightarrow \text{Cd}^{2 +} + 2 \, \text{Cl}^{-} + 2 \, \text{Ag}$ .

• A. $-105.5 \, JK^{- 1}$
• B. $-150.2 \, JK^{- 1}$
• C. $-75.7 \, JK^{- 1}$
• D. $-125.5 \, JK^{- 1}$

Answer 1

Answer: (D)

$\Delta S=+nF\frac{d E}{d t}$

$=2\times 96500\times \left(- 0.00065\right)$

$= - 125.5 \, \text{JK}^{- 1}$