问题 实验题

实验室制取硝基苯的主要步骤如下:

①配制一定比例的浓硫酸与浓硝酸的混合液,加入反应器。

②向室温下的混合酸中逐滴加入一定量的苯,充分振荡,混合均匀。

③在50~60℃下发生反应,直到反应结束。

④除去混合酸后,粗产品依次用蒸馏水和5%的NaOH溶液洗涤,最后再用蒸馏水洗涤。

⑤将用无水CaCl2干燥后的粗硝基苯进行蒸馏得到纯硝基苯。

填写下列空白:

(1)配制一定比例的浓硫酸和浓硝酸混合酸时,操作注意事项是__________________________________________________。

(2)步骤③中,为了使反应在50~60℃下进行,常用的方法是________。

(3)步骤④中洗涤、分离粗硝基苯应使用的仪器是______________________________。

(4)步骤④中粗产品用5%NaOH溶液洗涤的目的是_________________________。

(5)纯硝基苯是无色、密度比水________(填“大”或“小”),具有________气味的油状液体。

答案

(1)先将浓硫酸注入浓硝酸,并及时搅拌和冷却

(2)将反应器放在50~60℃的水浴中加热

(3)分液漏斗

(4)除去粗产品中残留的硝酸和硫酸

(5)大 苦杏仁

本题借助于苯的硝化反应设计为基本实验题,涉及了浓硫酸的稀释、水浴加热、物质分离、除杂以及硝基苯的物理性质等知识。

阅读理解

阅读理解。

     Some children are natural-born bosses. They have a strong need to make decisions, manage their

environment, and lead rather than follow. Stephen Jackson, a Year One student, "operates under the

theory of what's mine is mine and what's yours is mine," says his mother."The other day I bought two

new Star Wars light sabers (剑). Later, I saw Stephen with the two new ones while his brogher was

using the beat-up ones."

     "Examine the extended family, and you'll probably find a bossy grandparent, aunt, uncle or cousin

in every generation. It't an inheritable trait," says Russell Barkley, a professor at the Medical University

of South Carolina. Other children who may not be particularly bossy can bradually gain dominance

(支配地位) when they sense their parents are weak, hesitant, or in disagreement with each other.

     Whether it's inborn nature or developed character at work, too much control in the hands at the

young isn't healthy for children or the family, Fear is at the root of a lot of bossy behavior, says family

psychologist John Taylor. Children, he says in his book From Defiance to Cooperation, "have secret

feelings of weakness" and "a desire to feel safe." It's the parents' role to provide that protection.

     When a "boss child" doesn't learn limits at home, the stage is set for a host of troubles outside the

family. The overly willful and unbending child may have trouble obeying teachers or coaches, for

example, or trouble keeping friends. It can be pretty lonely as the top dog if no one likes your bossy

ways.

     "I see more and more parents giving up their power," says Barkley, who has studied bossy behavior

for more than 30 years."They bend too far because they don't want to be as strict as their own parents

were. But they also feel less confident about their parenting skills. Their kids, in turn, feel more anxious."

1. Bossy children like Stephen Jackson _____.

A. make good decisions

B. show self-centeredness

C. lack care from others

D. have little sense of fear

2. The underlined phrase "inheritable trait" in Paragraph 2 means _____.

A. inborn nature

B. developed character

C. accepted theory

D. particular environment

3. The study on bossy behavior implies that parents _____.

A. should give more power to their children

B. should be strict with their children

C. should not be so anxious about their children

D. should not set limits for their children

4. Bossy children may probably become _____.

A. relaxed

B. skillful

C. hesitant

D. lonely

5. What is the passage mainly about?

A. How bossy behavior can be controlled.

B. How we can get along with bossy children.

C. What leads to children's bossy behavior.

D. What effect bossy behavior brings about.

单项选择题