问题 选择题

甲酸香叶酯是一种食品香料,可以由香叶醇与甲酸发生酯化反应制得。下列说法中正确的是                (  )。

A.香叶醇的分子式为C11H18O

B.香叶醇在浓硫酸、加热条件下可发生消去反应

C.1 mol甲酸香叶酯可以与2 mol H2发生加成反应

D.甲酸香叶酯分子中所有碳原子均可能共平面

答案

答案:C

根据香叶醇的键线式,其分子式应为C11H20O,A错误;由香叶醇的键线式可知与羟基相连碳原子的相邻位置的碳原子上没有氢原子,无法发生消去反应,B错误;1 mol甲酸香叶酯中有2 mol碳碳双键,可以与2 mol H2发生加成反应,C正确;甲酸香叶酯中存在一个手性碳,此碳及其连接的碳不可能处于同一个平面上,D错误。

单项选择题
单项选择题

The United States is usually given credit for creating and developing the musical comedy as it is known today. The first musical shows were based (1) everyday American life and the (2) development of the form took place in the United States for more than half a century. (3) the early 1970s, (4) , the London theater has (5) the Broadway stage.

The Black Crook, which opened at Niblo’s Garden in New York City on Sept. 12, 1866, is usually (6) as the inspiration for musical comedy. A troupe of French ballet dancers (7) to be stranded in New York without work (8) a fire damaged the theater (9) they had been booked. In order to keep a (10) to them, the theater producer put the dancers into a melodrama written by Charles M. Barres.

The first stage production that was (11) a musical comedy was a show that was (12) from the Prince of Wales Theater to the Gaiety Theater in London in 1892. Staged by George Edwards, the show called In Town featured a chorus line of Gaiety Girls. The (13) year A Gaiety Girl was equally successful, and a (14) of the show played in New York in the same year. When it was (15) in newspapers, it was designated a musical comedy and regarded as a new (16) of entertainment.

It did not take the form long to (17) in the United States. Almost (18) one of the most renowned talents of the American stage went to work on his own musicals. The singer-dancer George M. Cohan staged Little Johnny Jones in 1904. Cohan, (19) own life story was made into the musical George M (1968), also wrote the books, words, and (20) for Forty-five Minutes from Broadway ( 1906 ), The Little Millionaire ( 1911 ), The Song and Dance Man ( 1923 ), and American Born (1925).

11()

A.thought

B. considered

C. mentioned

D.meant