将化合物 A 溶于水后加入 NaOH 溶液有黄色沉淀 B 生成。 B 不溶于氨水和过量的 NaOH 溶液, B 溶于 HCl 溶液得无色溶液, 向该溶液中滴加少量 SnCl 2 溶液有白色沉淀 C 生成,继续滴加 SnCl 2 溶液沉淀变灰,最后变成黑色。向 A 的水溶液中加入 AgNO 3 溶液有白色沉淀 E 生成 , E 不溶于 HNO 3 溶液但可溶于氨水。请给出 A 的化学式。
【简答题】A.He will choose a new topic to write the essay. B.He will choose the novel written by Shakespeare as the topic. C.He refuses to accept the man's advice. D.He is on the wrong track.
【简答题】A.She will choose a new topic to write the essay. B.She used to choose the poetry written by Shakespeare as the topic. C.She refuses to accept the man's advice. D.She is on the wrong track.