Question
Predict the enthalpy change, free energy change and entropy change when ammonium chloride is dissolved in water and the solution becomes colder.
Solution
(i) Enthalpy change is positive since the solution becomes colder due to intake of heat from the solution.
(ii) Free energy change is negative since the dissolution of ammonium chloride takes place spontaneously.
(iii) Entropy change is positive since more ordered solid ammonium chloride is changed to less ordered solution of ammonium chloride containing larger number of ions 
