Problem on Physical Properties

Description:

Problem − Arrange the given set of compounds in the order of increasing boiling points.

1. Bromoethane, Bromoform, Chloromethane, Dibromomethane

2. 1 − Chloropropane, Isopropyl Chloride, 1 − Chlorobutane

Solution −

Boiling point increases with increase in molecular mass. For isomeric alkanes, boiling decreases with increase in branching.

Bromomethane, Bromoform, Chloromethane, Dibromomethane

CH₃Cl < CH₃Br < CH₂Br₂ < CHBr₃

With increase in molecular mass and the number of halogen atoms, boiling point also increases.

1 − Chloropropane, Isopropyl Chloride, 1 − Chlorobutane

CH₃CH(Cl)CH₃ < CH₃CH₂CH₂Cl < CH₃CH₂CH₂CH₂Cl

Isopropyl chloride has lowest boiling point due to branching, while butyl chloride has lower boiling point than propyl chloride due longer chain and increased molecular mass.