问题
选择题
可以鉴别乙酸溶液、葡萄糖溶液、乙醇溶液的试剂是( )
A．NaOH溶液
B．新制氢氧化铜悬浊液
C．石蕊试液
D．碳酸钠溶液
答案
答案：B
乙酸含有羧基，显酸性，能使氢氧化铜悬浊液澄清，葡萄糖含有醛基，和新制氢氧化铜悬浊液反应生成红色沉淀。乙醇和新制氢氧化铜悬浊液不反应，答案选B。
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可以鉴别乙酸溶液、葡萄糖溶液、乙醇溶液的试剂是( )
A．NaOH溶液
B．新制氢氧化铜悬浊液
C．石蕊试液
D．碳酸钠溶液
答案：B
乙酸含有羧基，显酸性，能使氢氧化铜悬浊液澄清，葡萄糖含有醛基，和新制氢氧化铜悬浊液反应生成红色沉淀。乙醇和新制氢氧化铜悬浊液不反应，答案选B。
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| Recently, one of my best friends, whom I've shared just about everything with since childhood, spent the weekend with me. Since I moved to a new town several years ago, we've both always looked forward to the few 1 a year when we can see each other. Over the weekend, we spent hours and hours, staying up 2 into the night, talking about the people she was 3 . She started telling me stories about her new boyfriend, about how he experimented with drugs and was 4 other self-destructive behavior. I was blown away! She told me 5 she had been lying to her parents about where she was going and even 6 out to see the guy. No matter how hard I tried to tell her that she deserved 7 , she didn't believe me. Her self-respect seemed to have 8 . I tried to 9 her that she was ruining her future and heading for big 10 , but she thought it acceptable to have such a boyfriend. By the time she left, I was really worried about her and 11 by the experience. It had been so frustrating, I had come 12 to telling her several times during the weekend that maybe we had just 13 too far apart to continue our friendship-but I didn't. I put the 14 of friendship to the final test. We'd been friends for far too long. I had to hope that she 15 me enough to know that I was trying to save her from 16 herself. I wanted to believe that our friendship could conquer 17 . A few days later, she called to say that she had thought long and hard about our 18 , and then she told she had broken up with her boyfriend. I just listened on the other end of the phone with tears of 19 running down my face. It was one of the truly 20 moments in my life. | ||||
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