Write the equation of reactions and indicate their type C2h4-c2h2-c6h6-c6h5no2

Let us write down the solution, compose equations for the chain of transformations:
C2H4 = H2 + C2H2 – dehydrogenation reaction, acetylene was obtained;
3C2H2 = C6H6 – trimerization, occurs with the participation of a hot coal catalyst, benzene is released;
C6H6 + HNO3 = C6H5NO2 + H2O – the substitution reaction occurs when heated in the presence of sulfuric acid as a dehydrating agent, nitrobenzene is formed.
These reactions show the connection of unsaturated hydrocarbons (alkenes) with aromatic hydrocarbons. The reaction products have practical applications, for example, nitrobenzene is used as a basis for the production of aniline.