问题 选择题

下列离子在指定溶液中一定能大量共存的是(  )

①加入Al能放出H2的溶液中:Na、K、N、Cl、S2

②在pH=1的溶液中:Na、N、S2、S

③由水电离的c(H)=1012mol/L的溶液中:Cl、HC、N、N、F

④加入Mg能放出H2的溶液中:Mg2、N、Cl、K、S

A.②④

B.④

C.②③

D.①②

答案

答案:B

选项①中溶液可能显酸性,也可能显碱性。如果显酸性,则在NO3的存在下,S2不能大量共存,也不能生成氢气;②中溶液显酸性,则在NO3的存在下,S2、S不能大量共存;③中溶液中水的电离是被抑制的,所以溶液可能显酸性,也可能显碱性。由于HC既能与酸反应,也和碱反应,所以一定不能大量共存;④中溶液显酸性,一定可以大量共存,答案选B。

阅读理解

They’re WILD animals

By Ernst-Ulrich Franzen

March 11, 2010 (3) Comments

The story about the woman who lost some fingers while feeding a bear at a zoo in Manitowoc, after she ignored warnings and barriers(栅栏), reminded me of the story I heard about a couple who put their baby on the back of a wild horse in South Dakota to get a really cute picture. We all do silly things at times — no one is immune — but treating wild animals as lovely pets has to fall into a special category. Teddy bears and Disney movies aren’t actually representative of real bears.

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1. TosaLeft - Mar 11, 2010 10:46AM

Don’t you think that maybe, just maybe some alcohol was involved?

2. tk421 - Mar 11, 2010 11:09 AM

It was already approved that alcohol was involved. Stories that begin with a drunk person saying “Hey, I got an idea, watch this!” rarely end well.

3. Tristan Kloss - Mar 11, 2010 11:41 AM

Alcohol certainly isn’t involved when people decide to keep “pets” like chimpanzees, baby tigers, etc. Stupidity, definitely. Dogs are pets because of thousands of years of domestication. Even farm animals, which have been kept by humans for thousands of years as well, aren’t let in the house. So why keep animals that treat human contact with, at best, indifference(冷淡、不在乎) and, at worst, violence?

60.In Ernst-Ulrich Franzen’s opinion, the woman lost her fingers because ________.

A. the zoo keepers didn’t warn her of the danger       

B. she didn’t know the bear was a wild animal

C. she was somehow influenced by cartoon characters

D. she climbed over the barriers and angered the bear

61.TosaLeft thinks the wounded woman ________.

A. may have been drunk                                          B. may be a little stupid

C. was addicted to wine                                           D. fed wine to the bear

62.tk421 means a drunk person ________.

A. should be forbidden to enter the zoo                     B. usually gets himself into trouble

C. is often fond of making up stories                         D. usually likes to show himself off

63.What does Tristan Kloss think of people treating wild animals as pets?

A. Kind.                       B. Illegal.                                   C. Loving.                           D. Stupid.

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