Identify the correct order for the given property for following compounds.
Choose the correct answer from the option given below :

Solution

Chemistry ma’am · 3 steps

Heavier halogen or more halogens means higher boiling point and density; branching lowers boiling point.

1. Boiling point rules. Boiling point rises with molar mass, because a bigger molecule has stronger van der Waals forces. For isomers with the same mass, more branching makes the molecule more compact, so it boils lower.
2. Density rule. Density rises with the mass of the halogen (Cl < Br < I) and with the number of halogen atoms. Extra CH₂ groups add volume more than mass, so they lower density.

   Statement	What really happens	Verdict
   (A) b.p. C₂H₅Cl < C₃H₇Cl < C₄H₉Cl	Chain grows, molar mass grows: 12 < 47 < 78 °C	Correct
   (B) density C₂H₅Br < C₂H₅Cl < C₂H₅I	Should be C₂H₅Cl < C₂H₅Br < C₂H₅I, since Cl is lighter than Br	Wrong
   (C) b.p. CH₃CH₂Br < CH₃CHBr₂ < CH₃CBr₃	Each extra Br raises the molar mass a lot	Correct
   (D) density CH₃CHBrI < CH₃CH₂CH₂Br < CH₃CH₂CHBrCl	CH₃CHBrI (molar mass 235, carries Br and I) is the densest, not the lightest	Wrong
   (E) b.p. 1-chlorobutane > 1-chloro-2-methylpropane > 2-chloro-2-methylpropane	Same mass, branching increases: 78 > 69 > 51 °C	Correct

3. So. (A), (C) and (E) are correct, while (B) and (D) get the density order wrong. The answer is (c).

The idea to keep. For haloalkanes, heavier halogen or more halogen atoms raises both boiling point and density. Among isomers, more branching means a lower boiling point.

Answer from the NTA final answer key. Solution by PrepWiser.