题目

For all the dinner table, a glass of milk seems to be a constant, at least it was when I was growing up. It was widely believed that milk was integral in building strong bones and teeth. There’s no doubt that dairy products (乳制品), and milk in particular, are high in protein and calcium, and most milk products are supplemented with Vitamin D and A. While it’s well known that our bones need calcium, some studies suggest that high calcium intake doesn’t necessarily lower a person’s risk for fractures (骨折). A Harvard study found that people who drank two or more glasses of（14分）常温下，将某一元酸HA和NaOH溶液等体积混合，两种溶液的浓度和混合后所得溶液的pH如下表： 实验编号 HA NaOH 混合溶液的pH 甲 C(HA)＝0.2 mol·L－1 C(NaOH)=0.2mol·L－1 pH=a 乙 C(HA)=c1 mol·L－1 C(NaOH)=0.2mol·L－1 pH=7 丙 C(HA)=0.1 mol·L－1 C(NaOH)=0.1mol·L－1 pH=9 丁 pH=2 pH＝12 pH=b 请回答：（1）不考虑其他组的实验结果，单从甲组情况分析，如何用a（混合溶液的pH）来说明HA是强酸还是弱酸？                                                    。（2）若考虑其他组的实验结果，则c1        (填“＜”、“＞”或“＝”)0.2 mol·L－1；乙组实验中HA和NaOH溶液混合前，HA溶液中C(A－)与NaOH溶液中C(Na＋)的关系是     。A.前者大            B.后者大        C.二者相等      D.无法判断（3）从丙组实验结果分析，该混合溶液中离子浓度由大到小的顺序是               ；其中，C(A－)=          mol·L－1（不能做近似计算，回答准确值，结果不一定要化简）。（4）丁组实验中，HA和NaOH溶液混合前C(HA)      　（填“＜”、“＞”或“＝”）C(NaOH)；    b       　　7（填“＜”、“＞”或“＝”）