Target Exam

CUET

Subject

Chemistry

Chapter

Organic: Haloalkanes and Haloarenes

Question:

Arrange the following compounds in order of in increasing boiling points:

(A) Bromomethane
(B) Bromoform
(C) Chloromethane
(D) Dibromomethane

Choose the correct answer from the options given below:

Options:

(A), (B), (C), (D)

(A), (C), (B), (D)

(B), (A), (D), (C)

(C), (A), (D), (B)

Correct Answer:

(C), (A), (D), (B)

Explanation:

The correct answer is Option (4) → (C), (A), (D), (B)

Boiling point increases with increase in molecular mass and intermolecular van der Waals forces. Heavier halogen atoms lead to stronger intermolecular attractions and therefore higher boiling points.

Reasoning:

  • $(C)$ Chloromethane ($CH_{3}Cl$): Lowest molecular mass, weakest intermolecular forces, lowest boiling point.
  • $(A)$ Bromomethane ($CH_{3}Br$): Higher mass than chloromethane, so boiling point increases.
  • $(D)$ Dibromomethane ($CH_{2}Br_{2}$): Two bromine atoms, much higher mass and stronger attractions.
  • $(B)$ Bromoform ($CHBr_{3}$): Three bromine atoms, highest molecular mass and strongest intermolecular forces, so highest boiling point.