JEE Main 2026 — Haloalkanes and Haloarenes Question with Solution
JEE Main 2026 (08 April Shift 2)
Question
n-Butane on monochlorination under photochemical condition gives an optically active compound "P". "P" on further chlorination gives dichloro compounds. The number of dichloro compounds obtained (ignore stereoisomers) is:
Choose an option
Show full solutionCorrect option: B
Correct answer
B
Step-by-step explanation
The structure of n-butane is .
Monochlorination of n-butane gives two structural isomers: 1-chlorobutane and 2-chlorobutane.
Among these, 2-chlorobutane () contains a chiral carbon atom and is optically active. Thus, the optically active compound "P" is 2-chlorobutane.
Further chlorination of 2-chlorobutane can take place at any of the four carbon atoms, yielding the following dichloro compounds (ignoring stereoisomers):
1. Chlorination at C-1: (1,2-dichlorobutane)
2. Chlorination at C-2: (2,2-dichlorobutane)
3. Chlorination at C-3: (2,3-dichlorobutane)
4. Chlorination at C-4: (1,3-dichlorobutane)
Therefore, 4 structurally distinct dichloro compounds are obtained.
Answer:
Monochlorination of n-butane gives two structural isomers: 1-chlorobutane and 2-chlorobutane.
Among these, 2-chlorobutane () contains a chiral carbon atom and is optically active. Thus, the optically active compound "P" is 2-chlorobutane.
Further chlorination of 2-chlorobutane can take place at any of the four carbon atoms, yielding the following dichloro compounds (ignoring stereoisomers):
1. Chlorination at C-1: (1,2-dichlorobutane)
2. Chlorination at C-2: (2,2-dichlorobutane)
3. Chlorination at C-3: (2,3-dichlorobutane)
4. Chlorination at C-4: (1,3-dichlorobutane)
Therefore, 4 structurally distinct dichloro compounds are obtained.
Answer:
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