Arrange each set of compounds in order of increasing boiling points.
Bromomethane, Bromoform, Chloromethane, Dibromomethane.
Chloromethane < Bromomethane < Dibromomethane < Bromoform. Boiling point increases with increase in molecular mass. As the size and mass of halogen atoms increase, the magnitude of van der Waal forces increases, resulting in higher boiling points.
1-Chloropropane, Isopropyl chloride, 1-Chlorobutane.
Isopropyl chloride < 1-Chloropropane < 1-Chlorobutane. For isomeric haloalkanes, boiling points decrease with increase in branching. Isopropyl chloride is branched and has lower boiling point than 1-Chloropropane. 1-Chlorobutane has higher molecular mass, hence higher boiling point.
Explanation
The textbook directly provides these answers in section 6.6. For part (i), boiling point increases with molecular mass as van der Waal forces increase. For part (ii), branching decreases boiling point among isomers, and larger molecules have higher boiling points due to greater molecular mass.