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如何鉴别Na_2CO_3溶液和NaHCO_3溶液是高考的一个考点。我们平时教学或大多数的资料中经常给出以下两种方法。方法1:分别加入等浓度、等体积的稀盐酸。实验现象:Na_2CO_3溶液中一开始无气体,后来有气泡;NaHCO_3溶液中有大量气体产生。方法2:分别加入等浓度、等体积CaCl_2溶液。实验现象:Na_2CO_3溶液中产生白色沉淀,NaHCO_3溶液无明显变化。一般中学化学教师会认为以上两种方法都是正确的。CO_3~(2-)需要得到2个质子才能形成H_2CO_3,进而放出
How to identify Na_2CO_3 solution and NaHCO_3 solution is a test of the college entrance examination. Our usual teaching or most of the information is often given the following two methods. Method 1: Add equal concentration, equal volume of dilute hydrochloric acid. Experimental phenomenon: Na_2CO_3 solution has no gas in the beginning, then there are bubbles; a large amount of gas is generated in the NaHCO_3 solution. Method 2: Equal concentrations of CaCl 2 solution were added separately. Experimental phenomena: white precipitate appeared in Na_2CO_3 solution, and there was no obvious change in NaHCO_3 solution. Generally, secondary school chemistry teachers think that the above two methods are correct. CO_3 ~ (2-) need to get two protons to form H_2CO_3, and then released