根据短文，选择正确答案。

    Mr. White looks out of his window. There is a boy at the there side of the street. The boy takes some bread out of a bag and begins eating it. There is a very thin dog in the street too.

    The boy says to it, “Come here, good dog. I'll give you some bread.” The dog is hungry and goes to the boy, but he does not give it any bread. He kicks the dog. It runs away.

    Then Mr. White comes out of his house and says to the boy, “I'll give you a shilling.”

    The boy is happy and says,“Yes”. “Come here,” Mr. White says. The boy goes to him, but Mr. White doesn't give him a shilling. He hits him with a stick.

    The boy cries and says, “Why do you hit me? I don't ask you for any money.” “No,” Mr. White says, “And the dog doesn't ask you for any bread, but you kick it.”

①图中用石墨作电极，在一定条件下电解饱和食盐水制取ClO₂．则阳极产生ClO₂的电极反应式为____．

②电解一段时间，当阴极产生的气体体积为112mL（标准状况）时，停止电解．通过阳离子交换膜的阳离子的物质的量为____mol；阴极区pH将____．

物理小组的同学们在研究通过可变电阻的电流I和它两端电压U的关系时，记录了实验数据如下表所示。请根据表中数据归纳出通过可变电阻的电流I和它两端电压U的关系的关系：U=____ 。

民族团结、民族友好是我国历史发展的主流，下列事件反映这一主题的是(   )                                                                  
①郑和下西洋②文成公主和金城公主入藏③鉴真和尚东渡日本④清朝设驻藏大臣，协同达赖、班禅共同管理西藏事务