Question

Arrange the following in decreasing order of their boiling points.
(A). N-butane
(B). 2-methylbutane
(C). N-pentane
(D). 2,2-dimethylpropane
A. AgtBgtCgtD
B. BgtCgtDgtA
C. DgtCgtBgtA
D. CgtBgtDgtA

Answer 1

Correct Answer - D
As the number of carbon atom increases, boiling point increases. Boiling point decreases with branching 2,2-dimethylpropane,
`overset("2,2-dimethylpropane,")underset("Boiling point=282.5 K")(H_(3)C-overset(CH_(3))overset(|)underset(CH_(3))underset(|)C-CH_(3))" "underset("Boiling point=309.4K")(H_(3)C -overset("n-pentane")(CH_(2)-CH_(2))-CH_(2)-CH_(3))`
`overset("2-methylbutane")underset("Boiling point = 301K")(H_3C-H_2C-undersetoverset(|)(CH_3)(HC)-CH_3) " " overset("n-butane")underset("Boiling point = 273K")(H_3C-H_2C-CH_2-CH_3`