Question

Based only on intermolecular forces, which of the following would be the least soluble in CH₃CH₂OH? a) NaCl b) KCl c) NH₃ d) CH₃COOH

Answer 1

Answer: CH₃CH₂OH

Explanation: The intermolecular forces of hydrogen bonding, dipole-dipole interactions, and London dispersion have a significant role in influencing solubility in CH₃CH₂OH.

Both ionic compounds, NaCl and KCl, dissolve in water through ion-dipole interactions. These compounds have large lattice energies, which implies it takes a lot of energy to dissolve them in CH₃COOH and break the ionic bonds.

(c) The polar molecule NH3 is capable of forming a hydrogen bond with CH₃CH₂OH. Therefore, it is anticipated that NH3 will be more soluble in CH₃CH₂OH than NaCl or KCl.

(d) The polar compound CH₃COOH is capable of forming a hydrogen bond with CH₃CH₂OH.

Therefore, NaCl is predicted to be the least soluble in CH₃CH₂OH based solely on intermolecular forces.

Answer 2

CH3CH2OH , NH3 and CH3COOH are all able to form strong hydrogen bonds with water molecules making them soluble in water.

Between NaCl and KCL being more soluble depends on hydration energy and lattice energy. The size of Sodium ions is smaller so they easily get hydrated and therefore the hydration energy is more compared with lattice energy.

Therefore KCL is the least soluble in water.