The number of possible structural isomers for a compound with the molecular formula $C_7H_{16}$ is

In which of the following reactions does the carbon number not change on product formation?
$(i)$ Hydrogenation
$(ii)$ Alkyl halide reduction
$(iii)$ Wurtz reaction
$(iv)$ Decarboxylation
$(v)$ Kolbe reaction

What is catenation?

Identify the correct statements from the following:
$(i)$ Petrol and $CNG$ operated automobiles cause less pollution.
$(ii)$ Alkanes having tertiary hydrogen can be oxidised to alcohols by $KMnO_4$.
$(iii)$ Methane can be prepared by Kolbe's electrolytic method.
$(iv)$ Alkyl chloride on reduction with zinc and dilute hydrochloric acid gives alkane.

Arrange the following in decreasing order of their boiling points:
$(A)$ $2-$Methylbutane
$(B)$ $2,2-$Dimethylpropane
$(C)$ Pentane
$(D)$ Hexane

The general formula of an alkane is: