Skip to content
dronacharya.ai
← JEE Advanced 2014 · Paper 2
ChemistrySingle correct+3 / -1Question 22 of 60

JEE Advanced 2014 · Paper 2, Chemistry question 22

Isomers of hexane, based on their branching, can be divided into three distinct classes as shown in the figure.

The correct order of their boiling point is

Hexane isomers in three classes: I = 2,3-dimethylbutane and 2,2-dimethylbutane; II = 2-methylpentane and 3-methylpentane; III = n-hexane.
Choose one option
Answer and worked solution

Official answer: B

Branching lowers the boiling point. More branched molecules are more compact, with less surface for van der Waals contact.

  • Class III, n-hexane (no branching): highest (69 °C).
  • Class II, the methylpentanes (one branch): 60-63 °C.
  • Class I, the dimethylbutanes (two branches): lowest (50-58 °C).

(B) III > II > I

Topics:Alkanes
← Previous questionNext question →