试题与答案

下列各组离子一定能大量共存的是() A.加入铝粉有氢气产生的溶液中Na+、K+、

题型:选择题

题目:

下列各组离子一定能大量共存的是(    )

A.加入铝粉有氢气产生的溶液中Na+、K+、SO42-、Cl-、HCO-3

B.含有大量硝酸根离子的溶液中H+、Fe2+、SO42-、Cl-

C.常温下,c(H+)/c(OH-) = 1×10-10的溶液中NH4+、K+、Ca2+、Cl-

D.常温下pH=1的溶液中:MnO4-、NO3-、SO42-、Na+、Fe3+

答案:

答案:D

题目分析:A、加入铝粉有氢气产生的溶液说明该溶液为酸性但不能为硝酸溶液或为碱性溶液,HCO3-在酸性或碱性条件下都不能大量存在,错误;B、含有大量硝酸根离子的溶液中有H+存在,相当于有硝酸存在,Fe2+与H+、NO3-发生氧化还原反应不能大量共存,错误;C、常温下,c(H+)/c(OH-) = 1×10-10<1,说明c(H+)< c(OH-),溶液呈碱性,NH4+、Ca2+在碱性条件下不能大量存在,错误;D、常温下pH=1的溶液为酸性溶液,离子之间彼此不反应,可以大量共存,正确,答案选D。

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题型:阅读理解

     One kind of female butterfly mates only once in its life —and then closes its wings to avoid

"harassment" when pursued by persistent and unwanted males, a Japanese researcher said.

     Observations of the Small Copper Butterfly, a colourful orange and black butterfly, showed that some

females closed their wings when males flew by, but only when they were males of their own species, said

Jun-Ya Ide, an associate professor at Kurume Institute of Technology in Fukuoka, western Japan.

     "When we looked into why, the males were courting the females. They do this very stubbornly, so the

females sometimes try to get away-or prefer to stay unobserved," he added.

     Ide and his colleagues brought a model of a male butterfly near the females to test their reactions and

found that young females that had yet to mate kept their wings open, but those that had already mated

closed them.

     Not only can the persistent attentions of unwanted suitors harm the delicate females, fleeing from them

—with the male often in pursuit —uses up strength and can even shorten their lives, he added.

     "Closing their wings makes them less visible, helping them avoid communication with their own species. We figured they were trying to avoid harassment by males," Ide said.

1. What does the word "harassment" mean in the paragraph?

A. sexual invasion  

B. embarassment  

C. attack  

D. threat

2. Why some some females closed their wings when males flew by?

A. because the female butterfly mates only once in its life.

B. because they close their wings to avoid "harassment" when pursued by persistent and unwanted

males.

C. because they don’t like the male butterfly at all.

D. because they are afraid of the male butterfly.

3. According the the passage, which is correct?

A. The females closed their wings when males flew by.

B. The female butterfly mates only once in its life.

C. Only the model of a male butterfly can make the young female butterflies to keep their wings open.

D. Not only can the persistent attentions of wanted suitors harm the delicate females, fleeing from them

—with the male often in pursuit -- uses up strength and can even shorten their lives.

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