А) 4al+3o2=2al2o3 al2o3+3h2o=2al(oh)3 2al(oh)3+3h2so4==al2(so4)3 + 6h2o al2(so4)3+3bacl2==2alcl3+3baso4 б) H2+br2= 2Hbr Hbr+naoh=nabr+h2o 2nabr+caco3=na2co3+cabr2 cabr2+2naoh=ca(oh)2+nabr2