Question

Which of the following isomer having molecular formula C6H14 will give minimum number of monochloro derivatives?

1) Hexane 2) 2-Methylpentane 3)3-Methylpentane 4)2,3-Dimethyl butane

Answer 1

For hexane , there is symmetry of the structure at the 3-4 bond. So chlorine can attach to the first ,second and third carbons. So we will get three monochloride derivatives.

2- Methylpentane , chloride can attach to any of the five carbons(to the methyl group too) to give different structures.

Thus we will get five monochlorine derivatives .

For 3 - Methyl pentane , there is symmetry around the third carbon. So chloride can attach to the first ,second , third carbon and methyl group . So we will get four structure .

For 2,3 -Dimethylbutane , there is symmetry around the 2-3 bond . So chlorine can attach to first and second carbon to give two different structures.

HENCE 2,3 DIMETHYL BUTANE  GIVES MINIMUM NO. OF MONOCHLORO DERIVATIVES