问题 问答题

与金属的置换反应规律相同,非金属单质与盐反应也有类似的规律.根据下列反应:Cl2+2NaBr=2NaCl+Br2、Br2+2KI=2KBr+I2.回答下列问题:

(1)Cl2、Br2、I2的活泼性由弱到强的顺序是______.

(2)下列化学反应能发生的是______(填序号)

①2NaCl+I2=2NaI+Cl2   ②2KI+Cl2=2KCl+I2

(3)查阅资料知硫的活泼性比上述三种单质都弱.请用一个化学方程式证明此结论.______.

答案

(1)根据题意可得,非金属单质和盐反应具有和金属类似的规律,即活动性强的非金属可以把活动性弱的非金属置换出来,故答案为:I2<Br2<Cl2

(2)由于I2<Br2<Cl2,因此Cl2可以把I2从盐溶液中置换出来,故答案为:②

(3)由于S的活动性比I2、Br2、Cl2都弱,所以应该选用最弱的一个进行实验.即选用碘单质和硫化钠等反应,故答案为:I2+Na2S=S+2NaI

单项选择题
阅读理解

阅读理解。

     Food sometimes gets poisoned with harmful things. A person who eats such food can get an illness called

food poisoning. Food poisoning is usually not serious, but some types are deadly, The symptoms of food

poisoning usually begin within hours of eating the poisoned food. Fever is one of the most common symptoms.

     Certain microorganisms (微生物) cause most types of food poisoning. Bacteria and other microorganisms

can poison eggs, meat, vegetables, and many other foods. After entering the body, these tiny living things

release (释放) poisons that make people sick.

     Some chemicals can also cause food poisoning. They are often added to food while it is being grown,

processed, or prepaid. For example, many farmers spray chemicals on crops to kill weeds and insects. Some

people may have a bad reaction to those chemicals when they eat the crops.

     Some plants and animals contain natural poisons that are harmful to people. These include certain kinds of

seafood, grains, nuts, seeds, beans, and mushrooms.

     When people handle food properly, the risk of food poisoning is very small Microorganisms multiply rapidly

in dirty places and in warm temperatures. This means that people should never touch food with ditty hands or

put food on unwashed surfaces. Food should be kept in a refrigerator to stop microorganisms from gnawing.

Meat needs to be cooked thoroughly to kill any dangerous microorganisms. People should also wash food

covered with chemicals before eating it. Finally, people should not eat raid mushrooms or other foods that grow

in the wild. Some of these foods may contain natural materials that are poisonous to humans. In addition, some

types of fish can be poisonous.

     Most people recover from food poisoning after a few days of resting and drinking extra water. If people eat

natural poisons, they must go to the hospital right away to have their stomachs emptied.

1. Which of the following statements is NOT true?

A. Food when poisoned can make people sick.

B. Food poisoning means death.

C. Food poisoning comes in varieties.

D. Food poisoning can be serious.

2. We know from the passage that the symptoms of food poisoning _____.

A. are always accompanied by a fever

B. are too common to be noted

C. can be noticed within hours

D. can be ignored

3. Food poisoning can be caused by all the following EXCEPT _____.

A. some chemicals

B. low temperatures

C. some tiny living things

D. certain natural materials

4. From Paragraph 5, we can learn that _____.

A. mushrooms should not be eaten

B. vegetables are safer than meat and seafood

C. natural poisons are more dangerous than chemicals

D. different types of food should be handled differently

5. It can be inferred from the passage that _____.

A. natural materials are safe in food processing

B. chemicals are needed in food processing

C. food poisoning can be kept under control

D. food poisoning is out of control