题干

下列实验设计能达到实验目的是 ____

选项

实验目的

实验设计

A

从空气中获取纯净的氮气

用红磷燃烧除去空气中的氧气

B

清洗铁制品表面的铁锈

用适量的稀盐酸洗涤

C

除去混在二氧化碳中的氯化氢气体

把混合气体通过足量的氢氧化钠溶液

D

鉴别稀盐酸和氢氧化钠溶液

____

上一题 下一题 0.0难度 选择题 更新时间:2016-03-02 08:12:46

答案(点此获取答案解析)

B,酚酞试液

同类题4

阅读理解

B

    I'm David. Long ago I came to the city near my hometown to find a job. I met all kinds of difficulties and I used up all my money soon.

    It was dark outside one day. I got on a bus quietly. Suddenly, a passenger cried in a loud voice, "someone has stolen my money!" I felt nervous, because his money was in my hand. Some people suggested the driver drive the bus to the police station, but some were against it because they were in a hurry to go back home. The whole bus was very noisy. The driver then stopped the bus by the roadside and turned on the lights. At that time, one passenger said, "Turn off the lights and give the thief(小简)a chance to take out the money."Then the bus got dark.

    When I was still thinking about whether to take out the money or not, the lights were turned on again. There was no money on the floor. Someone said, "Give him one more chance." Then the lights were turned off again. I became even more nervous. The lights were turned on again but they got the same result.

    Then the passengers fell into an open discussion. Later, someone said, "Give him the last chance!" I felt awakened(醒悟的) and took out all the money when the lights were turned off again.

    For many years I have been grateful to those who gave me three chances. When the first and Second chances come, you may not be prepared well or don't have enough courage to act. When the third chance comes, you should know clearly what you should do.

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