题目

已知某溶液中存在OH-、H+、Cl-、四种离子。试分析溶液中溶质的种类及对应离子浓度的大小关系。 答案：溶液中溶质可能有以下三种情况：NH4Cl、NH4Cl和HCl、NH4Cl和NH3・H2O。（1）若溶质为NH4Cl，则溶液中存在如下“两个两”：电离平衡：H2OH++OH-水解平衡：+H2OH++NH3・H2O元素守恒：c（Cl-）=c（）+c（NH3・H2O）电荷守恒：c（OH-）+c（Cl-）=c（H+）+c（）很显然，离子浓度的大小关系为：c（Cl-）＞c（）＞c（H+）＞c（O4．听下面一段对话，回答第11-15五个小题．11． What are they talking about？A．Their weekends．    B．Their relatives．    C．Their homework．12． What did Frank do on Saturday？A．He did his homework．    B．He played tennis．    C．He visited his relatives．13．Whom did Frank go to the beach with？A．His brother．    B．His family．     C．His friends．14．When did Kate study for a math test？A．In the morning．    B．In the afternoon．     C．In the evening．15．Why did Kate feel more fun in the evening？A．She cleaned her room herself．B．She went to the movies with her friends．C．She had a party．