问题 选择题

下列实验设计能够成功的是(  )

编号实验目的实验操作及现象
A检验Na2O2试样是否变质为Na2CO3向试样中加入盐酸,产生无色无味的气体
B从碘水中萃取碘向碘水中滴加CCl4,振荡静置后分层,下层呈紫红色
C证明酸性条件H2O2氧化性比I2NaI溶液
稀硝酸酸化
30%双氧水
淀粉溶液
溶液变蓝色
D除去FeCl3溶液中的FeCl2杂质向FeCl3溶液中通足量Cl2后,充分加热煮沸,得到黄色溶液

A.A

B.B

C.C

D.D

答案

A.无论是否变质,加入盐酸都生成氧气,无色无味,不能证明是否变质,故A错误;

B.碘易溶于四氯化碳,四氯化碳与水互不相溶,并且四氯化碳的密度大于水,则静置后分层,下层呈紫红色,故B正确;

C.硝酸具有强氧化性,可氧化KI生成碘,不能证明过氧化氢的氧化性,故C错误;

D.向FeCl3溶液中通足量Cl2后,可除去FeCl3溶液中的FeCl2杂质,但不能煮沸,会导致FeCl3水解,故D错误.

故选B.

单项选择题

Eddie McKay, a once forgotten pilot, is a subject of great interest to a group of history students in Canada.
It all started when Graham Broad, a professor at the University of Western Ontario, found McKay’s name in a footnote in a book about university history. Mckay, was included in a list of university alumni who had served during the First World War, but his name was unfamiliar to Broad, a specialist in military history. Out of curiosity, Broad spent hours at the local archives in a fruitless search for information on McKay. Tired and discouraged, he finally gave up. On his way out, Broad’s glance happened to fall on an exhibiting case showing some old newspapers. His eye was drawn to an old picture of a young man in a rugby uniform. As he read the words beside the picture, he experienced a thrilling realization. "After looking for him all day, there he was, staring up at me out of the exhibiting case," said Broad. Excited by the find, Broad asked his students to continue his search. They combed old newspapers and other materials for clues. Gradually, a picture came into view.
Captain Alfred Edwin McKay joined the British Royal Flying Corps in 1916. He downed ten enemy planes, outlived his entire squadron as a WW1 flyer, spent some time as a flying instructor in England, then returned to the front, where he was eventually shot down over Belgium and killed in December 1917. But there’s more to his story. "For a brief time in 1916 he was probably the most famous pilot in the world," says Broad. "He was credited with downing Oswald Boelcke, the most famous German pilot at the time." Yet, in a letter home, McKay refused to take credit, saying that Boelcke had actually crashed into another German plane.
McKay’s war records were destroyed during World War Two air bombing on London-an explanation for why he was all but forgotten.
But now, thanks to the efforts of Broad and his students, a marker in McKay’s memory was placed on the university grounds in November 2007. "I found my eyes filling with tears as I read the word ’deceased’ next to his name," said Corey Everrett, a student who found a picture of Mckay in his uniform. "This was such a simple example of the fact that he had been a student just like us, but instead of finishing his time at Western, he chose to fight and die for his country.\

What is the text mainly about

A. The research into war history.
B. The finding of a forgotten hero.
C. The pilots of the two world wars.
D. The importance of military studies.

填空题