Verified answer

1) CH3COH + [O] = CH3COOH

    2CH3COOH + 2K = 2CH3COOK + H2↑

                                         t

2) CH3COOK + KOH  ------ > CH4 + Na2CO3

                t=1500C

3) 2CH4 ------------- > СН ≡ СH + 3H2↑

                                 K2Cr2O7+H2SO4, t

4) СН ≡ СH + H2O ----------------------------> CH3COH

                               Ni, t

5) CH3COH  + H2 -------------> CH3-CH2-OH

6) CH3-CH2-OH  + KBr --------------- > C2H5Br + KBr

7) 2C2H5Br + 2Na ------------ > CH3-CH2-CH2-CH3 + 2NaCl

8) CH3-CH2-CH2-CH3 + Br2 -------- > CH3-CHBr-CH2-CH3 + HBr

Вещество Х1 - СН ≡ СH (ацетилен или этин)

                  Х2 - CH3COH (этаналь или ацетальдегид)