题目

下列各组离子能大量共存于同一溶液中，且加入过量NaOH溶液或少许稀硫酸时，都能产生白色沉淀的是A．Ba2＋、Mg2＋、NO、CO  B．Na＋、Al3＋、Cl－、AlO2－C．Ba2＋、K＋、Cl－、HCO      D．NH、Fe3＋、Ba2＋、Cl－  答案：C解析: Ba2＋、Mg2＋与CO 产生沉淀，A错误。AlO2－与H+   Al3＋与OH-  AlO2－与Al3＋不共存。C加入过量NaOH溶液或少许稀硫酸时沉淀分别为BaCO3/BaSO4 ,D产生红褐色沉淀。 Rome was not built in a day. You should set ______ goals and work hard to achieve them. [     ]A. alternative      B. considerable       C. subjective      D. realistic