问题 选择题

根据下列实验内容得出的结论不正确的是

选项实验内容结论
A向澄清石灰水中通入某气体,产生白色沉淀该气体一不定是CO2
B向某溶液中滴加盐酸酸化的BaCl2产生白色沉淀该溶液一定含SO42-
C向某盐的水溶液中加入氢氧化钠加热,产生能使湿润的红色石蕊试纸变蓝的气体该盐一定是铵盐
D向沸水中滴加饱和FeCl3溶液得到红褐色液体该液体是Fe(OH)3胶体

答案

答案:B

题目分析:向澄清石灰水中通入某气体,产生白色沉淀,该气体不一定是CO2还可能是SO2,Z正确;向某溶液中滴加盐酸酸化的BaCl2产生白色沉淀,该溶液可能含SO42-还可能含有银离子;故选B。

点评:此类题目要求学生掌握常见的物质间的反应,特别是相似反应的不同点:如CO2和SO2都能使澄清石灰水变浑浊,通入过量又能变澄清;加入氯化钡能生成沉淀的既可以是和钡离子结合也可以是和氯离子结合。

阅读理解

阅读理解。

     A man once had a dream about the Black Forest in Germany. In his dream he was walking in the forest

when two men ran out and tried to throw him to the ground. He ran off as fast as he could, but they followed

him. He reached a place where he saw two roads in front of him, one to the right and the other to the left.

Which road should he take? He heard the two men behind him, getting nearer, and at the same time he heard

a voice in his ear. It told him to go to the right, and he did so. He ran on and soon came to a small hotel. He

was received there kindly and given a room, and he was saved from the two men. That was the dream.

     Twenty years later he was really in the Black Forest and as happened in the dream long ago, two men ran

out and tried to throw him down. He ran off, and came to a place with two roads, like in the dream. He

remembered the dream and took the road to the right He soon reached a small hotel, was taken in, and so

was safe. His dream of twenty years before had saved his life.

1. The Black Forest is ________.

A. a place in Germany

B. not a real place

C. invented by the writer

2. When he was walking in the forest, ________ ran after him.

A. two dogs

B. two tigers

C. two men

3. Finally he came to ________.

A. a forest

B. a small hotel

C. another dream

4. It was ________ that saved the man's life 20 years later.

A. a voice

B. the dream

C. someone else

5. The story tells us that ________.

A. a dream may come true sometime

B. people should not believe their dreams

C. dream can save one's life

单项选择题