问题 选择题

常温下,下列各组离子在指定溶液中能大量共存的是

①无色溶液中:K、Na、CO32、ClO

②pH=2的溶液中:Fe2+、Na、Mg2+、NO3-

③加入Al能放出H2的溶液中:Cl、HCO3-、SO42、NH4+

④由水电离出的c(OH)=1.0×10-13 mol·L-1的溶液中:Na、Ba2、Cl、Br

⑤含有较多Fe3的溶液中:Na、NH4+、SCN、HCO3-

A.①②

B.③④

C.①④

D.④⑤

答案

答案:C

题目分析:②pH=2的溶液呈酸性,Fe2+与NO3-会发生氧化还原反应,错误;③加入Al能放出H2的溶液可能呈酸性也可能呈碱性,其中HCO3-无论是在中一种环境中都无法共存,而NH4+只能在酸性中大量存在;⑤Fe3与SCN会发生络合反应,与HCO3-发生双水解反应,错误;

阅读理解

阅读理解。

     There was a pilot and four people traveling in a small plane. Suddenly there was something wrong with

 the machine and the smoke was coming up.

     "I must go and repair the machine," the pilot said and jumped out with one of the parachutes.

     A fat woman stood up. "I'm a doctor," she said, "I have to live to save the patients' lives." With that

 word she jumped out with another parachute.

     A thin businessman said, "I'm a very clever man! I can make good plans for our country; I can make a

 lot of money; I can..." Without finishing his words, he quickly picked up a pack and jumped out.

     Two men were left behind an old professor and a young mountain climber. Seeing the plane was going

  down fast, the professor said, "Young man, I'm old but you are still young. Please take the last

 parachute." The young mountain climber smiled, "Don't worry, sir. Just now the clever man jumped out

 with my backpack!"

1. There were  _____ people in the plane including the pilot.

    A. five

    B. one

    C. four

    D. six

2. Who thought he was a clever man?

    A. The pilot.

    B. The young mountain climber.

    C. The businessman.

    D. The professor.

3. The businessman jumped out with _____ .

    A. a parachute

    B. the climber's pack

    C. his own parachute

    D. the doctor

4. From the story we know that _____ might lose his life.

    A. the businessman

    B. the professor

    C. the mountain climber

    D. the doctor

5. What is the best title for this story?

    A. A Small Plane

    B. An Accident

    C. Clever or Stupid

    D. Travel by Air

填空题