Back to Directory
NEET CHEMISTRYMedium

The compound that will react most readily with gaseous bromine has the formula:

A

C3H6C_3H_6

B

C2H2C_2H_2

C

C4H10C_4H_{10}

D

C2H4C_2H_4

Step-by-Step Solution

  1. Identify the Compounds:
  • C4H10C_4H_{10}: Butane (Alkane, saturated).
  • C2H2C_2H_2: Ethyne (Alkyne, unsaturated, triple bond).
  • C2H4C_2H_4: Ethene (Alkene, unsaturated, double bond).
  • C3H6C_3H_6: Propene (Alkene, unsaturated, double bond).
  1. Reactivity Principle:
  • Alkanes react with halogens via free radical substitution, which typically requires UV light or high heat and is slower than addition reactions.
  • Unsaturated hydrocarbons (Alkenes/Alkynes) react with bromine via electrophilic addition. This reaction is generally fast and characteristic of unsaturation.
  • Alkenes vs. Alkynes: Alkenes are generally more reactive than alkynes towards electrophilic addition reactions [NCERT 11th, Ch 13, Sec 13.4.4]. This is because the π\pi-electron cloud in alkynes is more tightly held by the spsp-hybridised carbons compared to the sp2sp^2-hybridised carbons in alkenes.
  1. Compare Alkenes (Ethene vs. Propene):
  • Both Ethene (CH2=CH2CH_2=CH_2) and Propene (CH3−CH=CH2CH_3-CH=CH_2) undergo electrophilic addition.
  • Propene contains an electron-donating methyl group (−CH3-CH_3) which exerts a +I (Inductive) effect. This increases the electron density on the double bond, making it more nucleophilic and thus more reactive towards the electrophile (Br+Br^+) compared to ethene.
  • Therefore, Propene (C3H6C_3H_6) reacts most readily.
Practice Mode Available

Master this Topic on Sushrut

Join thousands of students and practice with AI-generated mock tests.

Get Started
Solved: CHEMISTRY Question for NEET | Sushrut