命题中以酸碱指示剂和溶液的酸碱度为出发点,针对性地考察溶液的酸碱性与pH值的关系、酸碱指示剂及其性质。此类解题的关键是知道pH的变化规律结合自身的识图分析能力,属常规基础知识考查题。例1(2016 南京)下列食物的近似pH如下,其中酸性最强的是()A.柠檬汁2.2-2.4B.番茄汁4.0-4.4 In the proposition, the acid-base indicator and the pH value of the solution are taken as the starting points. The relationship between the pH value and the pH value of the solution and the nature of the acid-base indicator are investigated. The key to solving this problem is to know the changing law of pH combined with its own ability to identify images, which is a common basic knowledge test questions. Example 1 (2016 Nanjing) The approximate pH of the following foods is as follows, with the strongest acidity being () A. Lemon Juice 2.2-2.4B. Tomato Juice 4.0-4.4