下列说法不正确的是（ ）
A．浊液的分散质粒子直径大于100nm，不能通过滤纸
B．胶体的分散质粒子直径小于100nm但大于1nm，能通过滤纸
C．利用丁达尔效应可以区分溶液和胶体
D．将氯化铁浓溶液和氢氧化钠浓溶液混合，能得到氢氧化铁胶体
A、分散质粒子直径大于100nm的分散系是浊液，浊液不能通过滤纸，故A正确；
B、分散质粒子直径小于100nm但大于1nm的分散系是胶体，胶体能通过滤纸，故B正确；
C、溶液无丁达尔效应、胶体具有丁达尔效应，所以丁达尔效应可以区分溶液和胶体，故C正确；
D、氯化铁浓溶液和氢氧化钠浓溶液混合，能得到氢氧化铁沉淀，不是氢氧化铁胶体，故D错误；
故选D．
选择恰当的主题句 Read the following text and choose the most suitable topic sentence from A—E for each paragraph. There is an extra one which you do not need.
Oliver Darrow, actor, talks about his daughter, Carmen． 72 It might have been nice to have more. I would have liked a son，but we just had Carmen. I see her as my best friend. I think she always comes to me first if she has a problem. We have the same sense of humour and share many interests，except that she’s crazy about animals，obsessed with them-she has always had dogs，cats，and horses in her life. 73 That’s when they need their parents most．But as soon as Carmen went to school，she seemed to grow up and grow apart from her family, and any father finds it difficult with a teenage daughter. She was very moody and had an odd group of friends. There was an endless stream of strange young men coming to our house. I remember I once got annoyed with her in front of her friends and she didn’t talk to me for days. 74 We sent her to a good school, but she wasn’t happy there. She left because she wanted to become an actress. So with my connections I got her into drama school. but she didn’t like that either. She worked for a while，doing small roles in films, but she must have found it boring because she gave it up，though she never really said why. She got married a few years ago; her husband’s a vet. They must be happy because t  hey work together. and she loves animals.We have the same tastes in books and music，When she was younger I used to take her to the opera-that’s nay passion-but she can’t have liked it very much because she hasn’t come with me for years. I don’t think she goes to the cinema or watches TV much. She might watch my films. but I don’t know. It’s not the kind of thing she talks to me about. 75 ．She’s a good daughter, but I don’t think she likes my new wife very much because she doesn’t visit us very often. I’m looking forward to being a grandfather one day. I hope she’ll have a son. |