Цепочка превращений: H2 - CH4 - CH3CI - C2H6 - C2H2
H2 - CH4 - CH3CI - C2H6 - C2H2 1) 2H2 + C = CH4 2) CH4 + Cl2 = CH3Cl + HCl 3) 2CH3Cl + 3Na = C2H6 + 2NaCl 4) C2H6 = C2H2 + 2H2