Question

10. (10 pts.) Identify the intermolecular forces present in the following compounds: Compound Intermolecular forces H- N- H H₃C CH₂ ç CC-C1 a. Which compound would you expect to have the higher boiling point? b. Justify your selection. C. Which compound would you expect to have the highest vapor pressure? d. Justify your selection.

Answer 1

Solution:

Intermolecular forces:

A) Ammonia ( NH3) :

Hydrogen bonding, dipole-dipole interactions

B) Acetone ( CH3COCH3):

Dipole-dipole interaction

C) Carbon tetrachloride (CCl4):

Vander waal forces or dispersion forces

Part A)

On the basis of intermolecular forces, NH3 has highest boiling point.

Part C) The higher boiling point of ammonia is due to the presence of hydrogen  bonding. Thus, more heat is required to boil the NH3.

Part D) Vapor pressure of CCl4 is minimum

Part E) Vapor pressure increases with decreasing boiling point. Since, boiling point of CCl4 is lowest hence it has highest vapor pressure.