Which one of the following cannot be prepared by Wurtz reaction?

$A$ hydrocarbon $C_5H_{12}$ does not react with chlorine in the dark but gives six monochloro compounds in bright sunlight. The hydrocarbon is:

What is obtained by the electrolysis of an aqueous solution of $CH_3COOK$?

The reaction of ethyl bromide and $n$-propyl bromide with sodium in ether gives .................

Which of the following is $NOT$ obtained when a mixture of methyl chloride and $n-$propyl chloride is treated with sodium metal in dry ether?

Heating of alkanes with fuming sulphuric acid or oleum at high temperature,which forms sulphonic acid,is called