(1)①Ba(OH) 2 ===Ba 2＋ ＋2OH － ；②NaHSO 3 ===Na ＋ ＋HSO 3 2- ；③HNO 3 ===H ＋ ＋NO 3 - ； ④Na 2 CO 3 ===2Na ＋ ＋CO 3 2- (2)③；①；②④ ...