问题 问答题

下列各组化学反应中,盐酸均是反应物.利用盐酸的弱氧化性的是(填编号)______;利用盐酸的弱还原性的是______;仅利用盐酸的酸性的是______.

(1)4HCl(浓)+MnO2

  △  
.
 
MnCl2+Cl2↑+2H2O   (2)2HCl+2Na=2NaCl+H2

(3)2HCl+CuO=CuCl2+H2O                  (4)HCl+HClO=Cl2↑+H2O

(5)CaCO3+2HCl=CaCl2+H2O+CO2↑           (6)Fe+2HCl=FeCl2+H2

答案

(1)反应4HCl(浓)+MnO2

  △  
.
 
MnCl2+Cl2↑+2H2O中氯化氢中的氯元素化合价升高,做还原剂具有还原性;氯化氢反应生成氯化锰和水,体现酸性,所以该反应中表现了盐酸的还原性和酸性;

(2)反应2HCl+2Na=2NaCl+H2↑中氯化氢中的氢元素化合价降低,做氧化剂,具有氧化性,表现盐酸的氧化性;

(3)反应2HCl+CuO=CuCl2+H2O是复分解反应,不是氧化还原反应,仅表现盐酸的酸性;

(4)HCl+HClO=Cl2↑+H2O中,氯化氢中氯元素化合价从-1价变化为0价,化合价升高作还原剂,具有还原性,表现盐酸的还原性;

(5)CaCO3+2HCl=CaCl2+H2O+CO2↑中,反应是复分解反应,不是氧化还原反应,仅表现盐酸的酸性;

(6)Fe+2HCl=FeCl2+H2↑中,氯化氢中的氢元素化合价降低,做氧化剂,具有氧化性,表现盐酸的氧化性;

综上所述:利用盐酸的弱氧化性的是(2)(6);利用盐酸的弱还原性的是(1)(4);仅利用盐酸的酸性的是(3)(5);

故答案为:(2)(6);(1)(4);(3)(5).

阅读理解

阅读理解。

     The Winter Olympics is also called the White Olympics. At this time, many colorful stamps will come

out to mark(标志) the great Games. The first stamps marking the opening appeared on January 25, 1932

in the United States for the 3rd White Olympics. From then on, stamps for the White Olympics became a

rule.

     During the 4th Winter Olympic Games, a group of stamps were off press in Germany in November

1936. It was the first time that the five rings appeared of the stamps of the White Olympics.

     In the 1950's, stamps of this kind became more colorful. When the White Olympics came, the host

countries as well as the non-host countries worked out stamps to mark those games. China also made

four stamps in February 1980, when the Chinese sportsmen began to take part in the White Olympics.

     Japan is the only Asian country that has ever held the White Olympics. Altogether, 14,500 million

stamps were sold to raise(筹集) money for this sports meet.

     Different kinds of sports were pictured on these small stamps. People can enjoy the beauty of the

wonderful movements of some sportsmen.

1. The White Olympics and the Winter Olympics _____.

A. are the same thing

B. are different games

C. are not held in winter

D. are held in summer

2.It was made a rule to work out stamps to mark the great world Games _____.

A. after the year 1936

B. after the 3rd White Olympics

C. before the 3rd White Olympics

D. before the year 1932

3.The Winter Olympics is held once _____.

A. every two years

B. every three years

C. every four years

D. every five years

4.Which of the following is TRUE?

A. Only the host countries can make stamps to mark the Games.

B. Only the non-host countries can make stamps to mark the Games.

C. All countries can make stamps to mark the Games.

D. Japan can't make stamps to mark the Games.

5. What may appear on the stamps of the White Olympics?

A. Basketball.

B. Table tennis.

C. Football.

D. Skating.

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