Four hydrocarbons are listed below. None contains a permanent dipole moment.
(a) Rank the four substances from highest to lowest normal boiling point. Clearly indicate any ties.
(b) For each consecutive pair in your ranking, state the primary factor (electron count, molecular shape/branching, or presence of π bonding) that accounts for the difference you predicted.
(c) One student argues that compounds I and IV must have identical boiling points because they have identical molar masses. Provide a reasoned rebuttal based on intermolecular forces.
(d) Suppose a mixture contains equal masses of substances I and II. When the mixture is gradually heated, which component is expected to reach its boiling point first? Justify quantitatively or qualitatively.