Chemistry - Liquid Solution Question with Solution | TestHub

For an ideal binary solution, the enthalpy of mixing is always zero ($\Delta H_{mix}=0$). The entropy of mixing is strictly positive ($\Delta S_{mix}>0$), so the $T\Delta S_{mix}$ curve lies entirely above zero. The Gibbs free energy of mixing is negative ($\Delta G_{mix}=-T\Delta S_{mix}<0$), meaning its curve lies entirely below zero. Graph (C) correctly shows a flat $\Delta H_{mix}$ at zero, a positive $T\Delta S_{mix}$ curve, and a negative $\Delta G_{mix}$ curve.