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A compound of molecular formula $C_7H_{16}$ shows optical isomerism, compound will be
A
2,3-dimethyl pentane
B
2,2-dimethyl butane
C
2-methyl hexane
D
None of the above
Detailed Solution
A compound shows optical isomerism if it has a chiral carbon (a carbon bonded to four different groups).
2,3-Dimethylpentane, $CH_3-CH(CH_3)-CH(CH_3)-CH_2-CH_3$ ($C_7H_{16}$): C-3 is bonded to H, $CH_3$, $CH(CH_3)_2$ and $C_2H_5$, four different groups. So it is chiral and shows optical isomerism.
2-Methylhexane has no carbon with four different groups (C-2 has two methyls).
2,2-Dimethylbutane is $C_6H_{14}$ and is not chiral.
So the compound is 2,3-dimethylpentane.
2,3-Dimethylpentane, $CH_3-CH(CH_3)-CH(CH_3)-CH_2-CH_3$ ($C_7H_{16}$): C-3 is bonded to H, $CH_3$, $CH(CH_3)_2$ and $C_2H_5$, four different groups. So it is chiral and shows optical isomerism.
2-Methylhexane has no carbon with four different groups (C-2 has two methyls).
2,2-Dimethylbutane is $C_6H_{14}$ and is not chiral.
So the compound is 2,3-dimethylpentane.