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全日制十年制学校高中课本第一册,学生实验九中,硅酸胶体制备方法是:“在一个试管里加入5至10毫升1M盐酸,并加入1毫升水玻璃,然后用力振荡,即得硅酸溶胶。”由于课文只指出使用韵盐酸浓度(1M),未说明水玻璃浓度,也未指明两份溶液的准确体积比,按此法进行实验,有时1分钟即形成胶冻,有时所制得的混和液要经过24小时后方能产生丁达尔效应。怎样才能做好制备硅酸胶体的实验呢?实验的适宜条件是什么?下面就这一问题作些探讨。硅酸显酸性,能跟溶液中的氢氧根发生反应。当溶液的pH值大于4.5时,所发生的反应是:
In the full-time 10-year high school textbook in the first volume, and in the student experiment 9, the silicic acid colloid is prepared by: adding 5 to 10 ml of 1M hydrochloric acid to a test tube, adding 1 ml of water glass, and then vigorously shaking it. Silicate sol.” Since the text only indicates the use of rhyme hydrochloride concentration (1M), the concentration of water glass is not specified, and the exact volume ratio of the two solutions is not specified. Experiments are performed according to this method, sometimes forming a jelly in one minute, sometimes The resulting mixture will produce the Tyndall effect after 24 hours. How can we do the experiment of preparing silicic acid colloid? What are the suitable conditions for the experiment? We will discuss this issue in the following. Silicic acid is acidic and reacts with hydroxide in solution. When the pH of the solution is greater than 4.5, the reaction that occurs is: