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:
Solution
Solution
The optically active monochloro product is 2-chlorobutane, CH–CHCl–CH–CH (C2 is a stereocentre).
A second chlorine can replace a hydrogen on any of the four carbons:
- on C1: 1,2-dichlorobutane
- on C2: 2,2-dichlorobutane
- on C3: 2,3-dichlorobutane
- on C4: 1,3-dichlorobutane (numbered from the other end)
Four constitutional isomers.
Answer: 4.
Answer checked against the official answer key. The solution is our own working.