1)
#2 1)K2O+H2O⇒2KOH ; 2) SO2+H2O⇒H2SO3 ; 3)BaO+H2O⇒Ba(OH)2
#3 1) H2O2+KMnO4⇒O2+MnO2+KOH+H2O
2)O2+2Ca⇒2CaO
3)CaO+H2O⇒Ca(OH)2