Question

Arrange the following compounds in increasing order of their boiling points.

(i)  \[\begin{array}{cc}
\ce{CH3}\phantom{..........................}\\
\backslash\phantom{......................}\\
\ce{ CH - CH2Br}\\
/\phantom{......................}\\
\ce{CH3}\phantom{...........................}
\end{array}\]

(ii) \[\ce{CH3CH2CH2CH2Br}\]

(iii) \[\begin{array}{cc}
\phantom{...}\ce{CH3}\\
\phantom{}|\\
\ce{H3C - C - CH3}\\
\phantom{}|\\
\phantom{..}\ce{Br}
\end{array}\]

Options

• (ii) < (i) < (ii)

• (i) < (ii) < (iii)

• (iii) < (i) < (ii)

• (iii) < (ii) < (i)

Answer 1

(iii) < (i) < (ii)

Explanation:

The boiling conditions of isomeric haloalkanes decrease as branching increases, because the higher the branching, the smaller the surface area. This decreases the molecule's Van der Waals force of attraction.

Order of boiling point:

2-Bromo-2-methylpropane < 1-Bromo-2-methyl propane < 1-Bromobutane