初三化学第258页有一个实验,要求学生用pH试纸分别测出稀盐酸、稀硫酸、稀硝酸的pH值,所给的三种酸均为(1:4)浓度。我认为这个浓度还不够稀。根据高校和一些中学化学教材的论述,我们一般讨论的pH值在0—14之间,通常的pH值测定仪器和试纸的适用范围为: 1.在水溶液中, 2.一般指的是常温, There is an experiment on page 258 of the third grade chemistry. Students are required to measure the pH of dilute hydrochloric acid, dilute sulfuric acid, and dilute nitric acid with a pH test paper. The three acids are all given at a concentration of (1:4). I think this concentration is not thin enough. According to the teaching materials of colleges and some middle schools, we generally discuss the pH value is between 0-14. The applicable range of the usual pH measuring instruments and test papers is as follows: 1. In aqueous solution, 2. Generally refers to normal temperature,