Pure methane can be produced by:

The reaction $CH_4 + Cl_2 \xrightarrow{uv \ light} CH_3Cl + HCl$ is an example of

Presence of which reagent will affect the reversibility of the following reaction,and change it to an irreversible reaction:
$CH_4 + I_2 \xrightarrow{hv} CH_3-I + HI$

Which of the following does not represent the correct major product?

Isobutyl magnesium bromide with dry ether and absolute alcohol gives

$A$ sample of $2,3-$dibromo$-3-$methylpentane is heated with zinc dust. The resulting product is isolated and then heated with $HI$ in the presence of red phosphorus. Indicate the structure that represents the final organic product formed in the reaction.