Which of the following does not give an alkane?

The compound $(X)$ on $(i)$ heating in the presence of anhydrous $AlCl_3$ and $HCl$ gas gives $2,4$-dimethylpentane,$(ii)$ aromatization gives toluene,and $(iii)$ cyclisation gives methylcyclohexane. The correct name of compound $(X)$ is:

What is the chief product obtained when $n$-butane is treated with bromine in the presence of light at $130^{\circ}C$?

Product $B$ is

Which of the following obtained products is not correct?

Explain the formation of alkanes by Kolbe's electrolysis method with an example. Alternatively,describe the preparation of alkanes from carboxylic acids via electrolysis.