Which isomer of hexane has only two different sets of structuraly equivalent hydrogen atom?

Options

A. 2,2-dimethylbutane
B. 2-methylpentane
C. 3-methylpentane
D. None of these

Answer

A

Explanation

(a) 2,2-dimethylbutane
`overset(p)(C)H_(3)-underset(underset(P)(C)H_(3))underset(|)overset(overset(P)(C)H_(3))overset(|)(C^(@))-overset(S)(C)H_(2)-overset(P)(C)H_(3)`
It has 2 sets of structurally different H-atoms, i.e., 12 primary and 2 secondary H-atoms.
(b) `underset("2-methyl pentane")(overset(P)(C)H_(3)-underset(T)overset(overset(P)(C)H_(3))overset(|)(C)H-overset(S)(C)H_(2)-overset(S)(C)H_(2)-overset(P)(C)H_(3))`
It has a 3 ets of sructurally different H-atoms, i.e., 9 primary, 4 secondary and 1 tertiary H-atoms.
(c) `underset("3-methyl pentane")(overset(P)(C)H_(3)-overset(S)(C)-underset(T)overset(overset(P)(C)H_(3))overset(|)(C)H-overset(S)(C)H_(2)-overset(P)(C)H_(3))`
It has a 3 sets of structurally different H-atoms, i.e. 9 primarry, 4 secondary. and 1 tertiary H-atoms.