Объяснение:
СH3-CH3 -> CH2=CH2 + H2
CH2=CH2 + H2 -> CH3-CH3
CH3-CH3 + Cl2 -> CH3-CH2-Cl + HCl
CH3-CH2-Cl + 2Na + Cl-CH2-CH3 -> CH3-CH2-CH2-CH3 + 2NaCl
