C2H4 (HCl) → X1 (Na, t) → X2 (AlCl3, t) → X3 (-H2, k, t) → X4 (H2O, H2SO4) → X5

C2H4+HCl=C2H5Cl2C2H5Cl+2Na=C4H10+2NaClCH3-CH2-CH2-CH3=CH3-CH(CH3)-CH3CH3-CH(CH3)-CH3= CH2=C(CH3)-CH3+H2CH2=CH(CH3)-CH3+H2O=CH3-CH(OH)(CH3)-CH3