题目

已知25 ℃时，Ka(HF)＝3.6×10－4 mol·L－1，Ksp(CaF2)＝1.46×10－10 mol3·L－3。现向1 L 0.2 mol·L－1 HF溶液中加入1 L 0.2 mol·L－1 CaCl2溶液，则下列说法中，正确的是( ) A．25 ℃时，0.1 mol·L－1 HF溶液中pH＝1 B．Ksp(CaF2)随温度和浓度的变化而变化 C．该体系中没有沉淀产生 D．该体系中HF与CaCl2反应产生沉淀 答案：D完形填空（共 15小题，每小题 1 分，满分15分） 阅读下面短文，从每小题A、B、C三个选项中，选出可以填入空白处的最佳选项，并将其字母标号填入题前的括号内。 A well-dressed man came into a famous jewellery （首饰）shop. He explained that he wished to buy a pearl（珍珠）for his wife’s birthday and that the  16   did not matter since business had been very good for him that year. After examin;ing a number of beautiful and valuable pearls, he chose a nice black one that _17_ $5000. He paid for that pearl , shook hands with the jeweler and left. A few days later the man returned and said his wife had liked that pearl _18_ that she wanted another one just like it. It had to be exactly the _19_ size and quality as she wanted a pair of earrings made. “Can you give me any advice on _20_ to get such a pearl?” said the man. The jeweler replied , “I would say it’s _21_ to find an exact one like that pearl.”     The rich man _22_ the jeweler to advertise in the newspaper, and offered $25.000 for that matching pearl. Many people answered that ad, _23_ nobody had a pearl that was just right. Just when the jeweler had _24__  hope, an old lady came in. To his _25_ , she took a wonderful pearl from her handbag. “I don’t like to sell it, ” she said _26_. “I inherited (继承)it from my mother, and my mother inherited from _27_, but now I really need money.” The jeweler was quick to pay her _28_ she changed her mind. Then he called the rich man’s hotel to tell the good _29_ to him. The rich man, however, was _30_ to be found. He had fled with the old woman a few more minutes before. 1. A. size                B. shape             C. price 2.A. spent               B. cost              C. took 3. A. a little              B. so much           C. at all 4. A. same               B. different           C. common 5.A. what               B. why               C. how 6. A. possible            B. easy               C. impossible 7. A. let                 B. make              C. asked 8. A. so                 B. but                C. and 9. A. found out           B. given up            C. come up with 10. A. disappointment      B. surprise             C. fear 11.A. happily             B. loudly             C. sadly 12.A. mine               B.his                 C. hers 13. A. when               B. before             C. after 14. A. news               B. advice             C. way 15. A. somewhere          B. anywhere           C. nowhere