题干

某温度下HF的电离常数Ka=3.3×104 mol•L1,CaF2的溶度积常数Ksp=1.46×1010(mol•L13.在该温度下将浓度为0.31mol•L1的HF溶液与浓度为0.002 mol•L1的CaCl2溶液等体积混合.下列说法正确的是(  )


A:该温度下,0.31 mol•L1 HF溶液的pH=2

B:升高温度或增大浓度,HF的电离平衡常数都将增大

C:两溶液混合后不会产生沉淀

D:向饱和的CaF2溶液中加水后,c(Ca2+)一定比加水前小

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答案(点此获取答案解析)

A,D

同类题4

阅读下面的文章,从每题所给的A、B、C、D四个选项中选出最佳选项。

    There is an old English saying, "Laughter is the best medicine." One person certainly would have agreed with this is Norman Cousins.

    Norman Cousins was the editor of a magazine called Saturday Review for almost forty years. He also 1 and spoke about world peace and anti-war issues(反战议题), traveling to many different countries to share his 2.

    In the 1960s, after returning to the United States from a busy and tiring trip to Europe. Mr. Cousins got 3. He discovered he had a strange disease that caused great pain in his bones(骨头).

    In less than a week after he got back, he could not 4 it. Every move that he made was painful. He was not able to 5 at night. The doctor told Mr. Cousins that they did not know how to cure (治疗)his problem and he might never 6 the illness. Mr. Cousins, however, refused to give up hope.

    Mr. Cousins thought that the illness could be caused by 7 thoughts. He did not want to take 8 to cure himself. Instead, he felt that happy thoughts or laughter might cure his illness.

    He began to experiment on himself while still in the hospital by watching comedy shows on television. Mr. Cousins quickly found that ten minutes of 9 laughter during the day gave him two hours of pain-free sleep at night.

    Deciding that the 10 could not help him, Mr. Cousins left the hospital and checked into a hotel room where he could 11 his experiments with laughter. For eight days, Mr. Cousins 12 in the hotel room watching comedy shows on television, reading amusing books, and sleeping whenever he felt 13. Within three weeks, he felt well enough to take a vacation to Puerto Rico where he began running on the beach for 14.

    After a few months, Mr. Cousins was 15 to carry on his work. He had laughed himself back to health.