Arrange each set of compounds in order of increasing boiling points.
(i) Bromomethane, Bromoform, Chloromethane, Dibromomethane.
(ii) 1-Chloropropane, Isopropyl chloride, 1-Chlorobutane.

Explanation

(a) For the same alkyl group, boiling point increases with the increase in size of the halogen atom. Therefore, boiling point af bromomethane is more than that of chloromethane. Further, the boiling point increases with increase in number of halogen atoms. Therefore, boiling point of bromoform is higher than that of dibromomethane, which is higher than that of bromomethane. Thus, the boiling point increases as :
`"Chloromethane" lt "Bromomethane" lt "Dibromomethane" lt "Bromoform"`.
(b) For the same halogen, boiling point increases with increase in sine of the alkyl group due to increase in van der Waals forces of attraction. Therefore, boiling point of 1-chlorobutane is more than that of 1-chloropropane. Further, the boil- ing point decreases as branching increases so that the boiling point of 1-chloropropune is higher than that of isopropyl chloride. Thus, the boiling point increases as:
`"Isopropyl chloride" lt "1-chloropropane" lt "1-chlorobutane"`