Oxidation of an alkene `(X)` gives a diol. Further oxidation gives a diketone. Which one of the following could be `X`?

Options

A. `(CH_(3))_(2)C=C(CH_(3))_(2)`
B. `CH_(3)CH=C(CH_(3))_(2)`
C. `CH_(3)CH=CH_(2)`
D. `C_(6)H_(5)CH=CHC_(6)H_(5)`

Answer

D

Explanation

Since a diol on further oxidation gives a diketone, each of the `C` atoms having `OH` group must carry one `H` each. In other words, the alkene must be disubstituted carrying one substituent one each doubly bonded `C` atom:
`C_(6)H_(5)CH=CHC_(6)H_(5)underset("alkaline"KMnO_(4))overset("Cold dulute")rarrC_(6)H_(5)-underset(OH)underset(|)CH-underset(OH)underset(|)CH-C_(6)H_(5)`
`overset([O])rarrC_(6)H_(5)-underset(OH)underset(|)overset(OH)overset(|)C-underset(OH)underset(|)(overset(OH)overset(|)C)-C_(6)H_(5)overset(-2H_(2)O)rarrC_(6)H_(5)-underset(O)underset(||)C-underset(O)underset(||)C-C_(6)H_(5)`