在高中化学的学习中存在着这样一类问题:化学试剂相同,但由于滴加顺序不同而出现了不同的化学反应,从而产生不同的实验现象。关于这方面的考题在近几年高考中屡次出现,现就这类型的几种情况做如下总结。一、碳酸钠溶液和盐酸溶液的反应1.向装有盐酸溶液的试管中滴加Na_2CO_3溶液至过量。实验现象:立即产生大量气泡。化学方程式:Na_2CO_3+2HCl=2NaCl+H_2O+CO_2↑。2.向装有Na_2CO_3溶液的试管中滴加盐酸溶液至 There is such a problem in high school chemistry learning that the chemical reagents are the same, but different chemical reactions occur due to the different dropping order, resulting in different experimental phenomena. Questions on this area in recent years, college entrance examination often appear, are several types of this type of situation to do the following summary. First, the reaction of sodium carbonate solution and hydrochloric acid solution 1. To the tube containing hydrochloric acid solution dropping Na_2CO_3 solution to an excess. Experimental phenomenon: immediately produce a lot of bubbles. Chemical formula: Na_2CO_3 + 2HCl = 2NaCl + H_2O + CO_2 ↑. 2. To the tube filled with Na2CO3 solution was added hydrochloric acid solution to