问题 选择题

如图所示,将铁棒和石墨棒插入1 L 1 mol•L-1食盐水中.下列说法正确的是(  )

A.若电键K与N连接,铁被保护不会腐蚀

B.若电键K与N连接,正极反应式是4OH--4e-=2H2O+O2

C.若电键K与M连接,若在溶液中滴入酚酞试液,则在石墨棒附近先出现红色

D.若电键K与M连接,当两极 * * 生28 L(标准状况)气体时,生成了1 mol NaOH

答案

若电键K与N连接,该装置没有外接电源,所以构成了原电池.

A、若电键K与N连接,该装置没有外接电源,所以构成了原电池;较活泼的金属铁作负极,负极上铁失电子生成二价铁离子进入溶液,所以铁不被保护,故A错误.

B、若电键K与N连接,该装置没有外接电源,所以构成了原电池;不活泼的石墨棒作正极,正极上氧气得电子生成氢氧根离子发生还原反应,电极反应式为2H2O+O2+4e-=4OH-,故B错误.

C、若电键K与N连接,该装置没有外接电源,所以构成了原电池;不活泼的石墨棒作正极,正极上氧气得电子生成氢氧根离子发生还原反应,电极反应式为2H2O+O2+4e-=4OH-,无色酚酞试液遇碱变红色,所以在溶液中滴入酚酞试液,则在石墨棒附近先出现红色,故C正确.

D、若电键K与N连接,该装置没有外接电源,所以构成了原电池;较活泼的金属铁作负极,负极上铁失电子生成二价铁离子进入溶液,正极上氧气得电子生成氢氧根离子,二价铁离子和氢氧根离子生成氢氧化亚铁,氢氧化亚铁不稳定被氧化成氢氧化铁,所以两极没有气体生成,且也没有氢氧化钠生成,故D错误.

故选C.

阅读理解

Nowadays, computer games are becoming more and more popular in many cities and towns. A lot of small shops along busy streets have been made into small game houses in order to get more money. These places are always crowded with people, especially young boys.

In the computer game houses, people spend a lot of money competing (较量) with the machines. It's hard for one to win the computer, but one can make progress after trying again and again. People have a kind of gambling psychology(赌博心理) when they play computer games.The more they lose, the more they want to win. When class is over, the school boys run to the nearby computer game houses.Little by little! (渐渐地), they forget all about their lessons and fall far behind others. Some of them can get enough money from their parents. But some of them are not lucky enough to get the money. They begin to take away other students' money and become thieves.

小题1:Who always go to the computer game houses?

A.Young girls

B.Young children

C.Young students

D.Young boys.小题2:People made small shops into small game houses in order to ______.

A.make computer games more popular

B.get more money

C.help people to learn computer better

D.make people happy小题3:What must be brought to play games in the game homes?

A. Tickets.   B Paper    C. Cards.   D. Money.

小题4:What will happen to the boys if they keep going to the game houses?

A.They will win a lot of money.

B.They will make a lot of good friends there.

C.They will fail in their study and even break laws.

D.They will live a happy life in the future.小题5:What is the passage mainly about?

A.Game houses have a bad effect on young boys.

B.More and more small shops have been made into game houses.

C.Young boys spend a lot of money playing computer games.

D.People play games better after trying again and again.

单项选择题 A1型题