Which is the correct increasing order of boiling points of the following compounds ?
1-bromoethane, 1-bromobutane, 1-bromopropane, 1-bromobenzene

Options

A. Butane `lt` 1-chlorobutane `lt` 1-bromobutane `lt` 1- iodobutane
B. 1-iodobutane `lt` 1-bromobutane `lt` 1-chlorobutane `lt` Butane
C. Butane `lt` 1-iodobutane `lt` 1-bromobutane `lt` 1- chlorobutane
D. Butane `lt` 1-chlorobutane `lt` 1-iodobutane `lt` 1-bromobutane

Answer

A

Explanation

Higher the surface area, higher will be the intermolecular forces of attraction and thus boiling point too. Boiling point increases with increase in molecular mass of halogen atom for the similar type of alkyl halide. Butane has no halogen atom and rest of all three compounds are halo derivatives of butane. Atomic mass of iodine is highest so the boiling point of 1-iodobutane is maximum among all the given compounds.