一、问题的提出在全日制十年制高中化学第二册第一章第三节“水的电离和溶液pH值”的教学中,曾有学生提出这样一个问题:某HCl溶液的[H~+]=10~(-6)M,若用水冲稀100倍后,溶液的pH值等于几?此时溶液显何性?我们把这一问题交由学生讨论,有的在课堂上提出;有的放在《学习园地》讨论,一度曾引起学生广泛的兴趣。对于这一问题,若解答成当溶液冲稀100倍后,[H~+]=10~(-8)M,故pH=8,则显 First, the question was raised in the teaching of full-time ten-year high school chemistry Book One Chapter III “water ionization and solution pH ”, students have asked such a question: a HCl solution [ H~+]=10~(-6)M. If 100 times diluted with water, the pH value of the solution is equal to the value of the solution. We put this question to the students for discussion, some in the classroom. Proposals; Some were discussed in the “Learning Corner” and once caused a wide range of students’ interest. For this problem, if the solution is diluted 100 times after the solution, [H~+]=10~(-8)M, so pH=8, then