Verified answer

Ответ:

С + 2H2 => CH4

CH4 + Cl2 => CH3Cl + HCl

2CH3Cl + 2Na => C2H6 + 2NaCl

____

3CH4 + 4O2 => C + 2CO + 6H2O

С + O2 => CO2

CO2 + Ca(OH)2 => CaCO3 + H2O

____

C2H6 => C2H4 + H2

H2 + CuO => Cu + H2O