Question

Intermolecular forces (IMPs) are the forces of attraction (or sometimes repulsion) that act between neighboring molecules All IMPs are based on etectrostatic interaction and are relatively weak compared to the Intramolecular forces that hold the atoms within a molecular together. In today, workshop you will practice to identify IMFs and predict their effect on boiling point melting point, vapor pressure and enthalpy of vaporisation (Delta Hvap). The Delta Hvap for a given molecule is the energy required to transform a given quantity of a substance from the liquid phase to the gaseous phase Delta Hvap values are usually measured in units of kJ/mol just like the Delta Hvap that we looked at In Topic 6. Consider the following compounds and the Information that follows List the type of intermolecular forces that are present in each compound List the compounds in order of decreasing intermolecular interaction strength.

Answer 1

(a). Benzene - London dispersion forces

       Napthalene - London dispersion forces

       Carbon tetrachloride - London dispersion forces

       Acetone - The intermolecular forces acting on two atoms of Acetone would be London Dispersion Forces and Dipole-Dipole Forces. This is because the atom has only side that is more positively charged than the other causing the Dipole-Dipole attraction.

       Acetic acid - Between two molecules of acetic acid there are 3 forces of attraction that affect them. These being the London dispersion force, the dipole-dipole force and hydrogen bonding.

       Benzoic acid - Hydrogen bonding because of the presence of OH group. It also have london forces.

(b). Benzoic acid > Acetic acid > Acetone > Napthalene > Benzene > Carbon tetrachloride