Petroleum mainly consists of.........

Which of the following has the lowest barrier to rotation about the indicated bond?

The correct order of boiling points of the following molecules is:
$(i)$ $n$-Hexane
$(ii)$ $2$-methylpentane
$(iii)$ $2,3$-dimethylbutane

The number of possible constitutional isomers of an alkane with the formula $C_6H_{14}$ is:

The reaction of propane with bromine in the presence of $UV$ light predominantly forms

In the process of cracking,what happens?