Reaction of Ethene with Bromine in \( CCl_4 \) will result in
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Vicinal- Dibromide
Bromine in carbon tetrachloride adds across a C=C double bond, one bromine atom going to each carbon of the double bond. The two Br atoms therefore end up on adjacent carbon atoms, which is called a vicinal (vic) dihalide:
\( \displaystyle \ce{CH2=CH2 + Br2} \xrightarrow{\ce{CCl4}} \ce{BrCH2-CH2Br} \)
The product, 1,2-dibromoethane, is colourless, so the reddish brown colour of bromine disappears; this is a test for unsaturation.
Why the other options are incorrect
Option (1) Gem-Dibromide — Incorrect. In a geminal dihalide both halogens are on the same carbon, as in 1,1-dibromoethane, \( \ce{CH3CHBr2} \), which is formed from ethyne and two molecules of HBr.
Option (3) Vinylic-Dibromide — Incorrect. A vinylic halide has the halogen on a carbon of a C=C double bond, as in \( \ce{CH2=CHBr} \); after addition to ethene no double bond is left.
Option (4) Allylic-Bromide — Incorrect. An allylic halide has the halogen on the carbon next to a C=C bond, as in \( \ce{CH2=CH-CH2Br} \). It is formed by substitution, and ethene has no such carbon.
NCERT (2026-27 edition):
From Hydrocarbons – …
