问题 选择题

将SO2和X气体分别通入BaCl2溶液,未见沉淀生成,若同时通入,有沉淀生成,则X气体不可能是         

A.CO2

B.NH3

C.C12

D.H2S

答案

答案:A

题目分析:A 、SO2和CO2的原理是类似的,都因为违背强酸制弱酸的原则而不能反应.因此不能生成沉淀.

B、中通入氨气后,和SO2反应生成亚硫酸铵,之后发生复分解反应生成亚硫酸钡沉淀.

C、氯气将亚硫酸根氧化成硫酸根,所以会有沉淀.

D、硫酸氢和二氧化硫反应生成硫沉淀.

点评:本题属于简单题,掌握弱酸不能制强酸是解题的关键。

单项选择题

I was a single parent of four small children, working at a low paid job. Money was always tight, but we had a (1) over our heads, food on the table, clothes on our backs, and if not a lot, always (2) . Not knowing we were poor, my kids just thought I was (3) . I’ve always been glad about that.

It was Christmas time, and although there wasn’t (4) for a lot of gifts, we planned to celebrate with a family party. But the big (5) for the kids was the fun of Christmas (6) .

They planned weeks ahead of time, asking (7) what they wanted for Christmas. Fortunately, I had saved MYM120 for (8) to share by all five of us.

The big (9) arrived. I gave each kid a twenty-dollar bill and (10) them to look for gifts of about four dollars each. Then everyone scattered. We had two hours to shop; then we would (11) back at the "Santa’s Workshop"

Driving home, everyone was in high Christmas spirits, (12) my younger daughter, Ginger, who was unusually (13) She had only one small, flat bag with a few candies—fiftycent candies I was so angry, but I didn’t say anything (14) we got home. I called her into my bedroom and closed the door, (15) to be angry again. This is what she told me.

"I was looking (16) thinking of what to buy, and I (17) to read the little cards on the ’Giving Trees’. One was for a little girl, four years old, and all she (18) for Christmas was a doll. So I took the card off the tree and (19) the doll for her. We have so much and she doesn’t have anything. "

I never felt so (20) as I did that day.

8()。

A.effort 

B.room 

C.time 

D.money

多项选择题 案例分析题