Question

Arrange the following molecules in increasing order of intermolecular forces : `C_(2)H_(6),CH_(3)NH_(2),CH_(3)F` and `CH_(2)F_(2)`

Answer 1

Greater the intermolecular forces, greater is the boiling point.
`C_(2)H_(6)` has only London forces,`CH_(3)NH_(2)` has hydrogen bonding and London forces. `CH_(3)F` and `CH_(2)F_(2)` have dipole-dipole attractions besides London forces, but dipole-dipole attractions in `CH_(2)F_(2)` are greater than those in `CH_(3)F`. Hence, order of boiling point is `C_(2)H_(6)(-88^(@)C)ltCH_(3)F(-78^(@)C)ltCH_(2)F_(2)(-52^(@)C)ltCH_(3)NH_(2)(-6^(@C)`.