The hydrocarbon [A] adds one mole of hydrogen in the presence of a platinum catalyst to form n-hexane. When [A] is oxidised vigorously with `KMnO_(4)`, a single carboxylic acid containing three carbon atoms is isolated. Give the strucure of [A] and explain the reactions.

Explanation

The compound combines with hydrogen to form normal hexane by consuming one mole of hydrogen, hence the hydrocarbons is n-hexene.
`underset(n-"Hexene")(C_(6)H_(12))+H_(2) to underset(n-"Hexane")(C_(6)H_(14))`
The position of double bond is indicated by its oxidation to propanic acid. Thus, the double bond is present in the middle of the chian (a symmetrical alkene).