Ba(OH)2过量：Ba2+ + OH- + H+ + SO42- = BaSO4↓ + H2O Ba(OH)2不足：Ba2+ + 2 OH- + 2 H+ + SO42- = BaSO4↓ + 2H2O
BA(OH)2+NAHSO4=BASO4+NAOH+H2O
