A:取一定量固体,溶解,向溶液中加入适量CaO粉末,充分反应后观察到有白色沉淀生成,说明原固体中一定含有Na2CO3
B:取一定量固体,溶解,向溶液中通入的CO2,观察到有晶体析出,说明原固体中一定含有Na2CO3
C:取一定量固体,加热,若产生的气体能使澄清石灰水变浑浊,说明原固体中一定含有NaHCO3
D:取一定量固体,滴加0.1mol/L盐酸至1L时,溶液呈中性,说明固体中各物质的物质的量总和为0.05 mol
Once an old man was walking in a street with his horse. It was raining hard. The old man was cold because he was walking in the rain. He wanted to stay in a restaurant. It was a quarter past three in the afternoon. The old man got to a small restaurant. A lot of people crowded in it. The old man couldn't come near the fireplace. He thought and thought.At last he said to the waiters, “ Take some fish to my horse.” The waiter and the other people were very surprised. The waitered said, “A horse doesn't eat fish.” The old man told the waiter, “ The horse is versatile. It can sing, dance and does all kinds of things. It can eat fish, too.” So the waiter took some fish to the horse. All the people in the restaurant rushed out to see the horse eat fish except(除了……之外) the old man. Now the old man sat beside the fire. After a while the waiter returned and said. “Your horse didn't eat any fish.” The old man said, “All right, take the fish back and put it on the table. I’ll eat it.”