问题 选择题

现有五种离子化合物A、B、C、D和E,都是由下表中离子形成的:

阳离子Na+     H+      Ba2+ 

阴离子OH   CO32–    SO42–  
为鉴别它们,分别完成以下实验,其结果如下:

①A溶液与B溶液反应生成无色气体,少量的该气体可以和C溶液反应生成沉淀E,沉淀E可与B溶液反应;

②B溶液与C溶液反应生成白色沉淀D,沉淀D不溶于B溶液;

请根据上述实验结果,选择:

(1)现有A、B、C三种物质的量浓度与体积都相等的溶液,若以不同顺序将它们中的两种混合起来,如果出现沉淀则过滤,再将滤液与第三种溶液混合起来,最终所得的溶液_____为酸性

A 、可能   B 、不可能
写出最终所得的溶液碱性的混合顺序_________。

答案

B

题目分析:
本题考查的是物质的鉴定与推断。难度适中。阴阳离子形成离子化合物注意离子之间结合物的溶解性。根据题意A、B、C三种物质为溶液,D、E为沉淀。A溶液与B溶液反应生成无色气体,A、B溶液分别为Na2CO3溶液和H2SO4溶液,沉淀E为碳酸盐,能溶于B溶液,所以B为H2SO4溶液,A为Na2CO3溶液。C溶液含有Ba2+,根据离子共存,C溶液只能是Ba(OH)2,E为BaCO3,D为BaSO4。A、B、C三种溶液混合有三种顺序,A、B混合再加入C,即Na2CO3和H2SO4混合生成Na2SO4,然后加入Ba(OH)2得到BaSO4和NaOH,溶液呈碱性。如果B、C混合后加入A,即Ba(OH)2和H2SO4混合生成BaSO4,再加入Na2CO3,最终溶液呈碱性。如果A、C混合后加入B,即Na2CO3和Ba(OH)2混合生成BaCO3和NaOH,再加入H2SO4最终得到Na2SO4,溶液呈中性。所以混合结果不可能呈酸性,呈碱性的结果有2种。

阅读理解

When a rare disease ALD threatened to kill the four-year-old boy Lorenzo, his parents refused to give up hope. Doctors explained that there was no cure for ALD, and that he would probably die within three years. But Lorenzo’s parents set out to prove the doctors wrong.

The parents devoted themselves to keeping their son alive and searching for a cure. But doctors and the families of other ALD patients often refused to take them seriously. They thought the efforts to find a cure were a waste of time, and drug companies weren’t interested in supporting research into such a rare disease.

However, the parents still refused to give up and spent every available hour in medical libraries and talking to anyone who would help. Through trial and error, they finally created a cure from ingredients (调料) commonly found in the kitchen. The cure, named "Lorenzo’s Oil", saved the boy’s life. Despite the good results, scientists and doctors remained unconvinced. They said there was no real evidence that the oil worked and that the treatment was just a theory. As a result, some families with ALD children were reluctant to try it.

Finally, the boy’s father organized an international study to test the oil. After ten years of trials, the answer is: the oil keeps ALD children healthy.

小题1:Doctors said that Lorenzo might die within three years because_____ .

A.they had never treated the disease before

B.Lorenzo was too young to be cured

C.no cure had been found for ALD

D.ALD was a rare disease小题2:The families of other ALD patients thought that _____ .

A.the research for the new cure would cost too much money

B.the efforts of Lorenzo’s parents were a waste of time

C.Lorenzo’s parents would succeed in finding a cure

D.Lorenzo’s oil was a real cure for ALD小题3: Scientists and doctors believed that Lorenzo’s Oil_____.

A.was really effective

B.was a success story

C.only worked in theory

D.would save the boy’s life小题4: From the passage we can conclude that_____.

A.doctors remain doubtful of the effectiveness of the cure

B.many ALD patients still refuse to use the oil

C.various cures have been found for ALD

D.the oil really works as a cure for ALD

多项选择题