Решение:
$$CH_2CH_2CH_2 + Br_2 \rightarrow BrCH_2CH_2CH_2Br$$
$$BrCH_2CH_2CH_2Br + Zn \rightarrow CH_3CH=CH_2 + ZnBr_2$$
$$CH_3CH=CH_2 + HCl \rightarrow CH_3CHClCH_3$$
$$CH_3CHClCH_3 + KOH \xrightarrow{спирт, t} CH_3CH=CH_2 + KCl + H_2O$$
$$CH_3CH=CH_2 + H_2 \xrightarrow{Ni, t} CH_3CH_2CH_3$$