实验室常用如图所示装置来研究气体的制取和性质，回答下列问题：

（1）写出仪器的名称：①____②____。A装置中长颈漏斗下端管口伸入液面下的目的是____。
（2）用高锰酸钾制取氧气的化学方程式为____，利用该反应制取氧气，可选用的发生装置是____ （填字母，下同），若选用C装置收集氧气，实验结束后的操作顺序是先将____ ，然后____ ，以防止水倒吸进入热的试管中，造成试管的破裂。
（3）在己学过的初中化学知识里，利用A装置可以制取二氧化碳，实验室常用石灰石与稀盐酸制取该气体，化学方程式为____ ，基本反应类型是____ ，收集二氧化碳应选用____ 装置。
（4）NO气体难溶于水，易被空气氧化，收集NO气体能选用的装置是____ 。

水处理厂（在两城镇之间或其中一城镇建厂，用管道将污水从各城镇向污水处理厂输送），依据经验公式，建厂的费用为f（m）=25•m^0.7（万元），m表示污水流量，铺设管道的费用（包括管道费） $g\left(x\right)=3.2\sqrt{x}$ （万元），x表示输送污水管道的长度（千米）；

已知城镇A和城镇B的污水流量分别为m₁=3、m₂=5，A、B两城镇连接污水处理厂的管道总长为20千米；假定：经管道运输的污水流量不发生改变，污水经处理后直接排入河中；请解答下列问题（结果精确到0.1）

根据材料内容，选择正确答案。

    Toronto is the biggest city in Canada. It is famous for the CN tower, Niagara Falls(尼亚加拉大瀑布)and some other famous places.

    The CN tower is 553 metres high. It is the world's highest tower. You can stand on a glass floor. Do you think it may break? If you think so, you are wrong, because the glass is very strong. If you look down from the CN tower, you will see a large stadium, the Skydome (天虹体育馆). The Skydome has a special(特殊的) roof(屋顶). The roof can open and close. So don't worry about the rain when you are watching a match there.

    Niagara Falls is one of the biggest falls in the world. It is made up of two falls. One is in the US. People call it American Falls. The other is in Canada. People call it Canadian Horseshoe Falls. The Horseshoe Falls drops from 52 metres high. It is 679 metres long. The sound of the water falling is so loud there. You cannot hear yourself talk! It is very exciting!