问题 问答题

常温下,将某一元酸HA和NaOH溶液等体积混合,两种溶液的物质的量浓度和混合后所得溶液的pH如下表:

实验编号HA的浓度/(mol?L-1NaOH的浓度/(mol?L-1混合溶液的pH

0.20.2pH=a

c0.2pH=7

0.10.1pH>7
请回答:

(1)不考虑其他组的实验结果,仅从甲组情况分析,如何用a的大小来说明HA是强酸还是弱酸 .

(2)不考虑其他组的实验结果,仅从乙组情况分析,c是否一定等于0.2 (填“是”或“否”).混合溶液中离子浓度c(A-)与c(Na+)的大小关系是 (填序号).

A.前者大    B.后者大     C.二者相等     D.无法判断

(3)从丙组实验结果分析,HA是 酸(填“强”或“弱”).该混合溶液中离子浓度由大到小的顺序是 .

答案
阅读理解

阅读理解:

      Once there was an old man in a town. He always forgot a lot of things. So his wife always had to say to

him, "Don't forget this!" 

      One day he went on a long trip alone. Before he left home, his wife said, "Now you have all these things.

They are what you need for your trip. Take care of your things during the trip." He went to the station, bought

a ticket and got on the train with it.

      About half an hour later, the conductor began to see the tickets. He came to the old man and said, "Will you

please show me your ticket?" The old man looked for his ticket in all his pockets, but he could not find it. He

was very worried. "I can't find my ticket. I really bought a ticket before I got on the train." said the old man. 

      "I believe you bought a ticket. All right, you don' t have to buy another one," said the conductor kindly. "But

how can I know where I'm going? I can't remember my station!" the old man said sadly.

1. The old man in the story was very ________. [ ]

A. kind

B. poor

C. forgetful (健忘的)

D. sad

2. Where is the ticket? [ ]

A. The old man forgot go buy it.

B. The old man could not remember where it was.

C. The old man showed it to the conductor.

D. The old man's wife took the ticket away.

3. The old man bought the ticket _______ he got on the train. [ ]

A. after

B. before

C. as

D. when

4. The conductor the old man _______. [ ]

A. didn't believe

B. laughed at

C. believed

D. felt sorry for

5. The old man was sad because ________. [ ]

A. he had to buy another ticket.

B. he lost all the things his wife gave him.

C. he did not know where he was.

D. He did not know where he should get off.

单项选择题