The 'middle oil' fraction of coal tar distillation contains

Aromatic compounds burn with a sooty flame because

Hexane $\xrightarrow[\substack{773 \ K \\ 10-20 \ atm}]{Cr_2O_3} X$ $\xrightarrow[\text{Anhydrous } AlCl_3]{CH_3COCl} Y$. $Y$ in the above sequence of reactions is

Which of the following is an example of a non-benzenoid aromatic compound?

Amongst the following,the compound that can be most readily sulphonated is

How would you convert the following compounds into benzene?
$(i)$ Ethyne $(ii)$ Ethene $(iii)$ Hexane