Consider the following hypothetical redox reaction $ \text{A}(s)+2\text{B}^{+}(aq)\rightarrow\text{A}^{2+}(aq)+2\text{B}(s):E_{\text{cell}}^0=0.295\ \text{V} $ The equilibrium constant of the reaction at 298 K will be: |
$ 10^5 $ $ 10^{10} $ $ 10^{-10} $ $ 10^{20} $ |
$ 10^{10} $ |
The correct answer is Option (2) → $ 10^{10} $ For the reaction $\text{A}(s)+2\text{B}^{+}(aq)\rightarrow\text{A}^{2+}(aq)+2\text{B}(s)\ E_{\text{cell}}^0=0.295$ This reaction shows that solid A is oxidized to $A^{2+}$ and $B^+$ ions are reduced to solid B Total electrons transferred $n = 2$ The relationship between standard cell potential and equilibrium constant is: $\Delta G^{\circ}=-nFE_{\text{cell}}^{\circ}$ $\Delta G^{\circ}=-RT\ln K$ Equating both: $-nFE_{\text{cell}}^{\circ}=-RT\ln K\Rightarrow\ln K=\frac{nFE_{\text{cell}}^{\circ}}{RT}$ Substituting Values: $n = 2$ $F=96500\ \text{C}/\text{mol}$ $E_{\text{cell}}^{\circ}=0.295$ $R=8.314\ \text{J}/\text{mol}\cdot\text{K}$ $T=298\ \text{K}$ $\ln K=(2\times96500\times0.295)/(8.314\times298)=22.98$ $K=10^{10}$ |