现行初中化学课本第193页习题中有这样一个问题:“……怎样检验生石灰中是否含有石灰石。”许多老师和学生是这样回答的:取试样,加入足量盐酸,如有气体放出,就将气体通入澄清石灰水中,看是否有混浊现象产生……。笔者为确定本题答案,反复进行多次实验。结果是,不管将氧化钙与碳酸钙按怎样的配比混和,加入盐 In the current junior high school chemistry textbook, page 193, there is such a problem in the exercise: “...how do you check whether or not lime contains limestone?” Many teachers and students responded by taking samples, adding enough hydrochloric acid, and releasing gas if necessary. Pass the gas into the clear lime water to see if any turbidity occurs... In order to determine the answer to this question, the author repeated experiments. As a result, no matter what proportion of calcium oxide and calcium carbonate are mixed, salt is added.