问题 选择题

FeCl3、CuCl2的混合溶液中加入铁粉,充分反应后仍有固体存在,则下列判断不正确的是

A 加入KSCN溶液变红色             B 溶液中一定含Fe2+

C 溶液中一定含Cu2+                 D剩余固体中一定含Cu

答案

AC

分阶段分析

①、当固体为铁、铜时,溶液中的Fe3+、Cu2+全部参加反应生成Fe2+和Cu,反应的反应方程式为:2FeCl3+Fe=3FeCl2

CuCl2+Fe=Cu+FeCl2

所以溶液中一定没有Fe3+、Cu2+,一定含有Fe2+

②当固体为铜时,溶液中一定没有Fe3+,Cu2+恰好全部参加反应或部分反应生成Fe2+和Cu,

所以溶液中一定没有Fe3+,可能含有Cu2+,一定含有Fe2+

A、溶液中一定不含Fe3+,所以加入KSCN溶液不变红色,故A错误.

B、通过以上分析知,溶液中一定含有Fe2+,故B正确.

C、通过以上分析知,溶液中可能含有Cu2+,故C错误.

D、通过以上分析知,剩余固体中一定含Cu,故D正确.

故选A、C.

阅读理解

阅读理解。

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      Now it's time to roll up your sleeves and start building. Learning the Net Communities provides

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1. The main purpose of the passage is to tell you _____.

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B. how to build your own website

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问答题