Question

Arrange the following in increasing order of boiling points.
(i) 3-methylpentane
(ii) 3-chloropentane
(iii) 3-bromopentane
(iv) 3,3-dichloropentane

• A. IV < III < II < I
• B. I < II < IV < III
• C. I < II III < IV
• D. II < I < IV < III

Answer 1

The correct option is B I < II < IV < III

3-bromopentane have higher molar mass than 3,3-dichloropentane so, it will have higher boiling point.
Between II and III, II has lower boiling point than III due to to large difference in their molar masses and I will have the lowest molar mass, thus has lowest boiling point.
Hence, correct order of boiling point is $I<II<IV<III$