问题 选择题

松油醇是一种天然有机化合物,存在于芳樟油、玉树油及橙花油等天然植物精油中,具有紫丁香香气,在香料工业中用途广泛,主要用于香皂及化妆品香料和调合香精.松油醇结构如图所示,下列有关松油醇的叙述正确的是(  )

A.松油醇的分子式为C10H20O

B.松油醇能发生加成反应、消去反应、氧化反应、酯化反应

C.松油醇存在酚类的同分异构体,分子中有2个手性碳原子

D.松油醇分子在核磁共振氢谱中有7个吸收峰

答案

A.松油醇的分子式为C10H18O,故A错误;

B.含C=C,能发生加成、氧化反应,含-OH,能发生消去、酯化反应,故B正确;

C.该物质不含苯环,只有一个C=C,不能存在酚类同分异构体,且含1个手性碳原子,故C错误;

D.该物质结构不对称,与同一个C相连的H相同,则松油醇分子在核磁共振氢谱中有8个吸收峰,故D错误;

故选B.

单项选择题

When Dave was eighteen, he bought a secondhand car for 200 so that he could travel to and from work more (1) than by bus. It worked quite well for a few years, but then it got so old, and it was costing him (2) much in repairs that he decided that he had better (3) it.

He asked among his friends to see if anyone was particularly (4) to buy a cheap car, but they all knew that it was falling to pieces, so (5) of them had any desire to buy it. Dave’s friend Sam saw that he was (6) when they met one evening, and said, "What’s (7) , Dave"

Dave told him, and Sam answered, "Well, what about advertising it in the paper You may (8) more for it that way than the cost of the advertisement!" Thinking that Sam’s (9) was sensible, he put an advertisement in an evening paper, which read "For sale: small car, (10) very little petrol, only two owners. Bargain at 50. " For two days after the advertisement first appeared, there was no (11) . But then on Saturday evening he had an enquiry. A man rang up and said he would like to (12) him about the car. "All right, " Dave said, feeling happy. He asked the man whether ten o’clock the next morning would be (13) or not. "Fine, " the man said, "and I’ll (14) my wife. We intend to go for a ride in it to (15) it. "

The next morning, at a quarter to ten, Dave parked the car in the square outside his front door, (16) to wait there for the people who had (17) his advertisement. Even Dave had to (18) that the car really looked like a wreck. Then, soon after he had got the car as clean (19) it could be, a police car stopped just behind him and a policeman got out. He looked at Dave’s car and then said, "Have you reported this (20) to us yet, sir\

16().

A.happening 

B.meaning 

C.turning 

D.failing

问答题 简答题