Question

Which branched chain isomer of the hydrocarbon with molecular mass `72mu` gives only one isomer of mono substituted alky halide ?
A. Tertiary butyl chloride
B. Neopentane
C. Isohexane
D. Neohexane

Answer 1

Correct Answer - B
Molar mass `=72 = C_(n) H_(2n) +2 = 12n + (2n + 2)`
`n =5`
Thus hydrocarbon is `C_(5) H_(12)`
Since it gives only single `C_(5)H_(11)` CI This suggests that `C_(5)H_(12)` is symmetrical
Hence it is containing all `12` equivalent H - atoms
`H_(3) Cunderset(CH_(3))underset(|)overset(CH_(3))overset(|)C-CH_(3) underset(Delta)overset(CH_(2))rarrH_(3)C-underset(CH_(3))underset(|)overset(CH_(3))overset(|)C-CH_(2)C1+HC1` .