Question

Which is the correct increasing order of boiling points of the following compounds?

1-bromoethane, 1-bromopropane , 1-bromobutane, Bromobenzene

(a) Bromobenzene < 1-bromobutane < 1-bromopropane < 1-bromoethane

(b) Bromobenzene < 1-bromoethane < 1-bromopropane < 1-bromobutane

(c) 1- bromopropane <1-bromobutane < 1- bromoethane < Bromobenzene

(d) 1-bromoethane < 1-bromopropane < 1-bromobutane < Bromobenze

Answer 1

Answer: (d). 1-bromoethane < 1-bromopropane < 1-bromobutane < Bromobenzene

Boiling point increases with increase in the size of the hydrocarbon part for the same haloalkanes. All the given haloalkenes contain the same halogen atom i.e., bromine but the number of carbon atoms in the hydrocarbon part of the molecule is increasing from ethane to benzene.

So, the boiling point is minimum for 1-bromoethane and maximum for 1-bromobenzene.