Question

Arrange the following in decreasing order of the boiling points
(a) n-butane (b) 2 methyl butane
(c) n-pentane (d) 2,2dimethypropane

Answer 1

(c)n-pentane < (a) n-butane < (b) 2 methyl butane (d) 2,2 dimethyl propane.

As branching inc. boiling point decreases.
As no. of carbon atoms inc. boiling point inc.

Answer 2

Answer: n-pentane > n-butane > 2 methyl butane > 2,2dimethypropane

Explanation:

More is the number of carbon atoms attached linearly or in the form of a long chain then more will be the boiling point of that compound.

Whereas if carbon atoms are attached through branching then there will be decrease in the boiling point of the compound.

The structure of n-butane is $CH_{3}CH_{2}CH_{2}CH_{3}$.

The structure of 2 methyl butane is $CH_{3}CH(CH_{3})CH_{2}CH_{3}$.

The structure of n-pentane is $CH_{3}CH_{2}CH_{2}CH_{2}CH_{3}$.

The structure of 2,2dimethypropane is $C(CH_{3})_{4}$.

Thus, we can conclude that boiling points in decreasing order are as follows.

    n-pentane > n-butane > 2 methyl butane > 2,2dimethypropane