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曾经听一位教师讲课,做制取硅酸实验时将稀盐酸滴入硅酸钠溶液中,边加边振荡,几分钟后产生了美丽的凝胶,很好看,学生很激动。有学生说:“我们写制取硅酸的化学方程式都是写成硅酸沉淀,如何得到硅酸沉淀呢?”教师说:“将硅酸钠滴加到盐酸中应该得到沉淀。”但是反过来实验却没有沉淀,连凝胶也没有了。教师解释说:“可能试管不净。”经洗刷后仍然没有任何现象,教师只好尴尬结束实验。有位教师讲到碳酸酸性比硅酸酸性强,很自信地补
Have to listen to a teacher lectures, do the preparation of silicic acid experiment drip dilute hydrochloric acid into sodium silicate solution, while adding edge oscillation, a few minutes later produced a beautiful gel, nice, the students are very excited. Some students said: “We write to take the chemical formula of silicic acid is written as silicic acid precipitation, how to get silicic acid precipitation? ” The teacher said: “The sodium silicate should be added to hydrochloric acid precipitation should be. ”But in the end the experiment did not settle, not even the gel. The teacher explained: “It is possible that the test tube is not clean.” After washing, there is still nothing left for the teacher to end the experiment in embarrassment. A teacher talked about carbonate acidity is stronger than silicic acid, very confident to make up