In the following reaction,$A$ is:

Natural gas is a mixture of

Which of the following reactions proceeds via a secondary free radical?

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.

The relative reactivity of $1^o H$,$2^o H$,and $3^o H$ in bromination reaction has been found to be $1 : 82 : 1600$ respectively. In the reaction $CH_3-CH(CH_3)-CH_3 \text{ (excess)} + Br_2$ $\xrightarrow{hv} CH_3-C(Br)(CH_3)-CH_3 \text{ (A)} + CH_3-CH(CH_3)-CH_2-Br \text{ (B)}$,the percentage yields of the products $(A)$ and $(B)$ are expected to be:

Which of the following $C-H$ bonds has the lowest bond dissociation energy?