Arrange the following alkenes in increasing order of their enthalpy of hydrogenation $(-\Delta H)$:

Two isomers $A$ and $B$ with molecular formula $C_4H_8$ give different products on oxidation with $KMnO_4$ in acidic medium. Isomer $A$ on reaction with $KMnO_4 / H^{+}$ results in effervescence of a gas and gives a ketone. The compound $A$ is ...... .

Consider compounds $A$, $B$ and $C$ with following structural formulae: $A = CH_{3} - CH_{2} - CH_{2} - CH_{2} - CH_{2} - OH$, $B = CH_{2} = CH - CH_{2} - CH_{2} - CH_{3}$, $C = HO - CH_{2} - CH_{2} - CH(OH) - CH_{3}$. For the conversion of $B$ from $A$, reagent $(D)$ required is . . . . . . and structural formula of product $(E)$ obtained when $C$ undergoes same reaction using excess reagent $(D)$ is . . . . . . .

Consider the given reaction. The total number of oxygen atoms present per molecule of the product $(P)$ is . . . . . .

Which of the following alkenes gives both $cis$ and $trans$ isomers upon catalytic hydrogenation?

In organic reactions, sodium in liquid ammonia is used as: