Fe(OH)2中一种白色沉淀,在空气中或在含有O2的水中容易被氧化而变色,难以看到它的“真面目”。为了解决这个问题,许多科学家对此实验作了研究和改进,以下三个图有一定的代表性。

(1)按照常规实验的要求,用胶头滴管滴加溶液时                         (填“能”或“不能”)伸入试管中,原因是                                                                                                                                 ,图I中,长胶头滴 管伸入液面下的目的是                                                                                                                                                                                                        

(2) 在图Ⅱ中,要观察到Fe(OH)2的生成,B管中的试剂可以是                                                 

实验操作的步骤是(反应试剂已加入)

                                                                                                                                                                                                                                                            

                                                                                                                                                                                                                                                            

若操作步骤①和②颠倒,能否看到Fe(OH)2白色沉淀?试说明理由:

                                                                                    

(3)若用图Ⅲ装置实验,阳极材料应选用                                                               ,阴极用石墨,阳极反应                                                                                                                             ,阴极反应是                            ,该实验有一明显的不足,不利于长久清楚地看到Fe(OH)2白色沉淀的生成,请指出并设法克服。                                                                              

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