A hydrocarbon, `C_(4)H_(8)`, neither decolourised bromine in carbontetrachloride nor reacted with hydrogen bromide. When heated to `200^(@)C` with hydrogen in presence of nickel catalyst, a new hydrocarbon, `C_(4)H_(10)` was formed. What was the orginal hydrocarbon?

Explanation

`C_(4)H_(8)` can have the following isomers:
`underset("1-Butene")(CH_(3)CH_(2))CH=CH_(2)" "underset("2-Butene")(CH_(3)CH=CHCH_(3))" "{:(CH_(2)-CH_(2)),("| |"),(CH_(2)-CH_(2)),("Cyclobutane"):}`
1-Butene and 2-butene are ruled out as these decolourise bromine in carbontetrachloride and also react with hydrogen bromide.
The hydrocarbon is cyclobutane. Cyclo-butane on reduction with hydrogen in presece of nickel opens up the ring and forms n-butane.
`underset(CH_(2))underset(|)CH_(2)-underset(CH_(2))underset(|)CH_(2)+H_(2)underset(200^(@)C)overset(Ni)toCH_(3)CH_(2)CH_(2)CH_(3)`