Hydrocarbons

The conversion of Propyne to Benzene can be brought out in 4 steps.

Choose the reagents to be used, in the proper sequential order, to bring out the conversion.

Reagents provided: alc. \(\mathrm{KOH}, \mathrm{H}_2 / \mathrm{Pd}, \mathrm{Na} /\) dry ether, \(\mathrm{HBr}, \mathrm{HBr} /\left(\mathrm{C}_6 \mathrm{H}_5 \mathrm{CO}\right)_2 \mathrm{O}_2\),
Soda-lime, \(\mathrm{Cr}_2 \mathrm{O}_3\) (high T and P), Conc. \(\mathrm{H}_2 \mathrm{SO}_4\)