1. CH4 → C2H6 → C2H5Br → C2H5OH → C2H4 → C2H6. 1) CH4 → C2H6 + H2, 2) C2H6 + Br → C2H5Br + HBr, 3) C2H5Br + H2O → C2H5OH + HBr, 4) C2H5OH → C2H4 + H2O, 5) C2H4 + H2 → C2H6. 2. C2H5OH → CH2 → C4H8 → C4H8 → C4H10. 1) C2H5OH → CH2 + H2O, 2) CH2 → C4H8, 3) C4H8 + H2 → C4H10.