搜题请搜索小程序“爱下问搜题”
问题 实验题

(10分)如图所示，在实验室里，通常利用浓硫酸与乙醇混合加热制乙烯，加热一段时间后观察到烧瓶中溶液变黑，装置(Ⅱ)中经硫酸酸化的高锰酸钾溶液褪色。

⑴甲同学认为酸性高锰酸钾溶液褪色，能证明乙烯被酸性高锰酸钾溶液氧化了，你认为甲同学的观点是否正确？____________(填“是”或“否”)，理由是___________(填字母)。

A．(Ⅱ)瓶中酸性高锰酸钾溶液褪色，能证明乙烯发生了氧化反应

B．(Ⅱ)瓶中酸性高锰酸钾溶液褪色，能证明乙烯发生了加成反应

C．(Ⅱ)瓶中酸性高锰酸钾溶液褪色，不能证明通入的气体是纯净物

D．(Ⅱ)瓶中酸性高锰酸钾溶液褪色，只能证明通入的气体一定具有还原性⑵乙同学取(Ⅱ)瓶中少量溶液于试管里，加入盐酸和氯化钡溶液，产生白色沉淀。据此他认为乙烯中一定混有SO2，你认为他的结论是否可靠？_______________(填“是”或“否”)，理由是__________________________________________________________。若你认为不可靠，请改进上述实验方案，证明乙烯中是否含有SO2：_______________________________。

⑶丙同学在装置(Ⅰ)和(Ⅱ)之间增加了一个装有足量_____________溶液的洗气瓶，即可证明乙烯能被酸性高锰酸钾溶液氧化。

答案

（10分）

(1)否（1分），C D（2分）。

(2) 否（1分），硫酸酸化的高锰酸钾溶液中本身就含有SO42-（2分），（Ⅱ）瓶中溶液换成品红溶液（2分）。

(3)氢氧化钠（2分）

⑴浓硫酸与乙醇混合加热制乙烯，产物中可能混有SO2、CH3CH2OH，这些物质都具有还原性，能酸性高锰酸钾溶液褪色，甲同学的观点不正确，理由是C D；⑵不正确，硫酸酸化的高锰酸钾溶液中本身就含有SO42-，干扰产生的SO42―的检验；（Ⅱ）瓶中溶液换成品红溶液⑶SO2是酸性氧化物能与碱反应，氢氧化钠等碱溶液。

填空题

两种基本测试方法中，______测试的原因之一是保证所测试模块中每一个独立路径至少要执行一次。
查看答案
单项选择题

There are many kinds of friends. Some are always (1) you, but don’t understand you. Some say only a few words to you, but understand you. Many people will step in your life, but only (2) friends leave footprints.
I shall always recall the autumn and the girl with the (3) . She will always bring back the friendship between us. I know she will always be my best friend.
It was the golden season. I could see the yellow leaves (4) with the cool (5) . In such a season, I liked walking alone on the roads covered with leaves, (6) to the sound of them.
Autumn is a (7) season and life is uninteresting. The free days always get me (8) . But one day, the sound of a violin (9) into my ears like a stream flowing in the mountains. I was so surprised that I jumped to see what it was. A young girl, standing in the wind, was (10) in playing her violin.
I had (11) seen her before. The music was so nice that I listened quietly. Lost in the music, I didn’t know that I had been (12) there for so long but my existence did not seem to disturb her.
Leaves were still falling. Every day she played the violin at the comer of the building (13) I went downstairs to watch her performance. I was the only listener. The autumn seemed no longer lonely and life became (14) . (15) we didn’t know each other, I thought we were already good friends. I believe she also loved me.
Autumn was nearly over. One day, when I was listening carefully, the sound suddenly (16) . To my astonishment, the girl came over to me.
"You must like music from the violin." she said.
"Yes. And you play very well. Why did you stop’." I asked.
Suddenly, a (17) expression appeared on her face and I could feel something unusual.
"I came here to see my grandmother, but now I must leave. I once played very badly. It was your listening every day that (18) me. " she said.
"In fact, it was your playing (19) gave me a meaningful autumn," I answered, " Let’s be friends. "
The girl smiled, and so did I. I never heard her play again in my life. I no longer went downstairs to listen to her. Only thick leaves were left behind. But I will always remember the fine figure of the girl. She is like a (20) —so short, so bright, like a shooting star giving off so much light that makes the autumn beautiful.

Ⅱ. 完形填空/Close

A．surprised

B．excited

C．encouraged

D．interested
查看答案