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食盐水的电解是氯碱工业的心脏部分,也是中学化学教学中的一个重要内容。可是,前几年,由于修正主义教育路线的回潮,我们学习这一内容时,教师不是通过开门办学到“大课堂”中去解决问题,而是关在“小课堂”里灌。因此,对于食盐水电解前为什么要净化,电解槽为什么要设隔膜,在阴极为什么是 H~+离子放电而不是 Na~+离子放电,在阳极为什么是 Cl~-离子放电而不是 OH~-离子放电,以及阴极液中 NaOH 的浓度为什么要控制在10％左右等问题,似懂非懂,有的即使在课堂上搞清楚了,但下课后把书本一合又忘了。
The electrolysis of salt water is the heart of the chlor-alkali industry and is an important part of chemistry teaching in middle schools. However, in the past few years, due to the resurgence of the revisionist education line, when we learned this content, teachers did not solve the problem by opening the door to running “big classrooms,” but instead placed themselves in “little classrooms.” Therefore, why do we need to purify the brine before electrolysis? Why do we have a membrane in the electrolytic cell? Why is the H+ ion discharge at the cathode instead of the Na~+ ion discharge? Why is the Cl~-ion discharge at the anode instead of the OH~- ion? The discharge and the concentration of NaOH in the catholyte should be controlled at about 10%, which seems to be incomprehensible, and even if it is clear in class, the book is forgotten after class.