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在初中化学教学中,稀盐酸与硫酸、可溶性氯化物与可溶性硫酸盐的鉴别方法是学生必须掌握的内容。有关它们的鉴别、推断题在历届各省市中考中屡见不鲜,但学生的得分率比较低,原因是学生只知道 AgCl 是不溶于水也不溶于酸的沉淀,而不知道稀硫酸、可溶性硫酸盐与硝酸银反应也可产生既不溶于水又不溶于酸的 Ag_2SO_4(微溶)白色沉淀,为了让学生能正确回答这类问题,我建议在硫酸这一节教学中,应补充稀硫酸与硝酸银溶液反应的演示实验或学生探究实验,以便学生掌握这部分知识。
In junior high school chemistry teaching, the identification method of dilute hydrochloric acid and sulfuric acid, soluble chloride and soluble sulfate is what students must master. Their identification and inference questions have been common in previous provincial and municipal exams, but the student’s score rate is relatively low because students only know that AgCl is insoluble in water and insoluble in acid precipitates. It is not known that dilute sulfuric acid, soluble sulfate and The silver nitrate reaction can also produce Ag_2SO_4 (slightly soluble) white precipitate that is neither soluble in water nor soluble in acid. In order to enable students to correctly answer such questions, I suggest that sulfuric acid and silver nitrate should be supplemented during the teaching of sulphuric acid. Demonstration experiment of solution reaction or student inquiry experiment so that students can master this part of knowledge.