题目

下列实验能达到实验目的的是A. 观察铁的吸氧腐蚀B. 石油分馏C. 制取并收集少量NO2D. 比较氯、碳、硅元素的非金属性 答案：【答案】A【解析】A.若Fe发生吸氧腐蚀，会导致左边试管内气体减少，压强减少，右边试管内导管中液面会上升，所以图中装置可观察铁的吸氧腐蚀，故选A；B.水应该从冷凝管的下口进，上口出，故不选B；C.NO2与水发生反应，不可用排水法收集，应该用向上排空气法，故不选C；D.稀盐酸不是氯的最高价 －Jenny took the 9∶10 bus to Hangzhou this morning． －Really? He ________ the 9∶00 Express．It is much more comfortable and faster to travel by train． [　　] A．could have taken B．need have taken C．must have taken D．would have taken