X和Y在周期表中相邻。CaCO3与X的单质高温反应，生成化合物B和一种气

X和Y在周期表中相邻。CaCO₃与X的单质高温反应，生成化合物B和一种气态氧化物；B与Y的单质反应生成化合物C和X的单质；B水解生成D；C水解生成E，E水解生成尿素。确定B、C、D、E、X和Y。

答案

B: CaC₂ C: CaCN₂ D: C₂H₂或Ca(OH) ₂ E: NH₂CN [C(NH)₂也可]

X: C Y: N

(各0.5分，共3分)

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