Determine substance X in the transformation scheme CaC2 → X → C2H2Cl4 1) C2H4 2) C2H2 3) C6H6 4) Ca (OH) 2

Here is the chain for the solution:
CaC2 – C2H2 – C2H2Cl4;
Let us write down the equations in sequence:
CaC2 + 2H2O = Ca (OH) 2 + C2H2 – hydration;
C2H2 + 2Cl2 = HC – Cl2 – CH – Cl2 – addition, tetrachloroethane.
The above reactions confirm the connection between inorganic and organic substances. Reaction products are of practical importance. Acetylene emits up to 500 degrees during combustion; it is used in gas welding of metals. Tetrachloroethane is used as a universal solvent.