Formation of a solution from two components can be considered as (i) Pure solvent $ightarrow$ separated…
(i) Pure solvent $ightarrow$ separated solvent molecules, $\Delta \mathrm{H}_{1}$
(ii) Pure solute $ightarrow$ separated solute molecules, $\Delta \mathrm{H}_{2}$
(iii) Separated solvent and solute molecules $ightarrow$ Solution, $\Delta \mathrm{H}_{3}$ Solution so formed will be ideal if
- $\Delta \mathrm{H}_{\text {soln }}=\Delta \mathrm{H}_{3}-\Delta \mathrm{H}_{1}-\Delta \mathrm{H}_{2}$
- $\Delta \mathrm{H}_{\text {soln }}=\Delta \mathrm{H}_{1}+\Delta \mathrm{H}_{2}+\Delta \mathrm{H}_{3}$
- $\Delta \mathrm{H}_{\text {soln }}=\Delta \mathrm{H}_{1}+\Delta \mathrm{H}_{2}-\Delta \mathrm{H}_{3}$
- $\Delta \mathrm{H}_{\text {soln }}=\Delta \mathrm{H}_{1}-\Delta \mathrm{H}_{2}-\Delta \mathrm{H}_{3}$
Solution
(According to Hess's law)
i.e., for ideal solutions there is no change in magnitude of the attractive forces in the two components present. /
Asked in: JEE-TOPICTESTS-CHEMISTRY