问题 选择题

下列各组四种无色溶液,只用酚酞就能鉴别的是(  )

A.KNO3、KCl、HCl、K2SO4

B.MgCl2、NaOH、HCl、NaCl

C.Na2SO4、NaCl、NaOH、HCl

D.NaOH、KOH、NaCl、H2SO4

答案

A、将酚酞分别滴进四种溶液中,溶液都是无色的,现象相同,无法鉴别,故A错误;

B、将酚酞分别滴进四种溶液中,酚酞变红的是氢氧化钠溶液,其余三种溶液中酚酞不变色,将氢氧化钠溶液分别滴进剩余的三种溶液中,有白色沉淀生成的是氯化镁,将生成的沉淀分成两份,将剩余的两种溶液分别滴进白色沉淀中,能使沉淀溶解的是盐酸,沉淀不溶解的是氯化钠,所以使用酚酞能将这四种溶液鉴别出来,故B正确;

C、将酚酞分别滴进四种溶液中,酚酞变红的是氢氧化钠溶液,其余三种溶液中酚酞不变色,将氢氧化钠溶液分别滴进剩余的三种溶液中,能使红色消失的是盐酸,剩余的两种溶液是氯化钠和硫酸钠溶液,将盐酸分别滴进剩余的两种溶液中,没有明显变化,无法鉴别氯化钠和硫酸钠,故C错误;

D、将酚酞分别滴进四种溶液中,酚酞变红的是氢氧化钠和氢氧化钾溶液,酚酞不变色的是氯化钠和硫酸,将剩余的两种溶液分别滴进变红的溶液中,能使红色褪去的是硫酸,不能使红色褪去的是氯化钠,但是氢氧化钠和氢氧化钾无法鉴别,故D错误;

故选B.

阅读理解

¤ While the 2008 Olympics were the first to be broadcast entirely in HD, the 2012 Olympics are the first to broadcast in HD as well as 3D. Sean Taylor, a spokesperson for Panasonic – provider of some of the technologies – said it effectively, “Each Games, from a technology perspective, tries to have a first. London will be the first HD and 3D Games.” The games were first televised in Berlin in 1936 and played on big screens about the city. Then came the first games to enter households (strictly in London that is) in 1948, followed by the first internationally televised games during the 1960 Olympics in Rome. And ever since, that feeling of physically standing in the crowd and watching these mighty contestants has only gotten clearer, more defined. Now, they more literally than ever actually compete in your living room.

§ A paradox is presented as the London games celebrate both the Industrial Revolution (a.k.a. the birth of pollution) and a spirit of committed environmentalism; London will be the first to actively measure its own carbon footprint during these games, designing a stadium and accommodations that cut-back on negative emissions when at all possible. They are also shooting for a world record via the “Javelin,” designed specifically to keep as many exhaust pipes at bay as humanly possible.

小题1:Which of the following statements is NOT true?

A. The Industrial Revolution first happened in England.

B. 2012 London Olympics is the first to broadcast in HD.

C. People couldn’t see the Olympic Games on TV 80 years ago.

D. 2012 London Olympics is more environmentally friendly than before.

小题2:What does the underlined word “paradox” probably mean in the text?

A.solid evidence

B.advanced thought

C.perfect opinion

D.contradictory view小题3:Where does this text probably come from?

A.a novel

B.a report

C.a diary

D.an essay小题4:What can be the best title for the text?

A.The History of Olympic Games.

B.Two Firsts about 2012 London Olympics

C.2012 London Olympics --- Eco-Conscious Games

D.2008 Beijing Olympics and 2012 London Olympics

单项选择题