The chemical reactions involved in the transformations of the given compounds are as follows:

CaCO₃ (calcium carbonate) -> CaO (calcium oxide) + CO₂ (carbon dioxide)
This reaction occurs when calcium carbonate is heated, producing calcium oxide and carbon dioxide gas.

CaO (calcium oxide) + C (carbon) -> CaC₂ (calcium carbide)
This reaction involves high temperature heating of calcium oxide and carbon to produce calcium carbide.

CaC₂ (calccium carbide) + 2H₂O (water) -> C₂H₂ (acetylene) + Ca(OH)₂ (calcium hydroxide)
This reaction occurs when calcium carbide reacts with water to form acetylene gas and calcium hydroxide.

C₂H₂ (acetylene) -> C₆H₆ (benzene)
Acetylene undergoes a series of chemical reactions to form benzene.

C₆H₆ (benzene) + 3H₂ (hydrogen) -> C₆H₁₂ (cyclohexane)
Benzene reacts with hydrogen in the presence of a catalyst to form cyclohexane.