Example

A binary mixture of at a certain $T$ and $P$ is having for one of its thermodynamic properties $(G^E)$ the following expression: $\frac{G^E}{R}T=A{x}_1{x}_2$ where $$ stands for mole fraction of species $($i$)$ and $A$ is a parameter dependent on $T$

Find expressions for $\frac{\frac{?}{\text{b}\text{a}\text{r}}(G{)}_i^{}}{RT}$ for both species

Verify the summability relation

Verify Gibbs Duhem equation

Find $\frac{\frac{?}{\text{b}\text{a}\text{r}}(G{)}_1^{}}{RT}$