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问题 选择题

常温下有体积相同的四种溶液：①pH=3的CH3COOH溶液 ②pH=3的盐酸 ③pH=11的氨水④pH=11的NaOH溶液。下列说法正确的是

A．若将四种溶液稀释100倍，溶液pH大小顺序：③＞④＞①＞②

B．③和④分别用等浓度的硫酸溶液中和，消耗硫酸溶液的体积：③=④

C．①与②分别与足量镁粉反应，生成H2的量：①<②

D．②和③混合，所得混合溶液的pH大于7

答案

答案：D

题目分析：强酸、强碱完全电离，弱酸、弱碱部分电离。当溶液的PH相同C(CH3COOH)＞ C(HCl) ;C(NH3·H2O) ＞ C(NaOH). 若将溶液稀释相同倍数，弱酸或弱碱的PH变化较小。故溶液pH大小顺序：③＞④＞②＞①A错误。如果溶液的体积相同，则n(CH3COOH)＞ n(HCl);n(NH3·H2O) ＞ n(NaOH). B．③和④分别用等浓度的硫酸溶液中和，由于n(NH3·H2O) ＞ n(NaOH).消耗硫酸溶液的体积：③＞④。错误。C．①与②分别与足量镁粉反应，由于n(CH3COOH)＞ n(HCl)生成H2的量：② <①。错误。D．②pH=3的盐酸C(H+)= 10-3mol/L;③pH=11的氨水C(OH-)=10-3mol/L盐酸是强酸完全电离，一水合氨是弱碱部分电离.C(HCl)= C(H+), C(NH3·H2O) ＞ C(OH-)= C(HCl).混合，②和③混合，因为碱过量，所以所得混合溶液的pH大于7。正确。

单项选择题

将活塞环安装到环槽中采用的工具是（）。

A．扩张器

B．拉伸器

C．扳手

D．用手拉开
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