BaCl2 + Na2SO4 = BaSO4 (осадок) + 2NaCl
C2H2 + H2O (t, Hg2+)= CH3COH
CH3COH + Ag2O (t)= CH3COOH + 2Ag
2CH3COOH + 2Na = 2CH3COONa + H2