[题目]已知由AgNO3溶液和稍过量的KI溶液制得的AgI胶体.当它跟Fe(OH)3胶体相混合时.能析出AgI和Fe(OH)3的混合沉淀.由此可知 A．该AgI胶粒带正电荷 B．该AgI胶粒带负电荷C．该AgI胶粒电泳时向阳极移动 D．Fe(OH)3胶粒电泳时向阳极移动题目和参考答案——青夏教育精英家教网—

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【题目】(双选)已知由AgNO3溶液和稍过量的KI溶液制得的AgI胶体，当它跟Fe(OH)3胶体相混合时，能析出AgI和Fe(OH)3的混合沉淀，由此可知

A．该AgI胶粒带正电荷 B．该AgI胶粒带负电荷

C．该AgI胶粒电泳时向阳极移动 D．Fe(OH)3胶粒电泳时向阳极移动

【答案】BC

【解析】AgI胶体与Fe(OH)3胶体相混合时，析出AgI和Fe(OH)3的混合沉淀，这是发生了胶体的聚沉，说明AgI胶粒与Fe(OH)3胶粒带相反电荷。而Fe(OH)3胶粒带正电，故AgI胶粒带负电。AgI胶粒带负电，故A错误、B正确；AgI胶粒带负电，故电泳时向阳极移动，故C正确；当它跟Fe(OH)3胶体相混合时，能析出AgI和Fe(OH)3的混合沉淀，说明Fe(OH)3胶粒吸附正电荷，电泳时向阴极移动，故D错误。

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