IB DP Chemistry: SL复习笔记8.2.6 pH Meters & Universal Indicator

pH Meters & Universal Indicator

  • The most accurate way to determine the pH is by reading it off a pH meter
  • The pH meter is connected to the pH electrode which shows the pH value of the solution


The diagram shows a digital pH meter that measures the pH of a solution using a pH electrode

  • A less accurate method is to measure the pH using universal indicator paper
  • The universal indicator paper is dipped into a solution of acid upon which the paper changes colour
  • The colour is then compared to those on a chart which shows the colours corresponding to different pH values


The diagram shows the change in colour of the universal indicator paper when dipped in a strong (HCl) and weak (CH3COOH) acid. The colour chart is used to read off the corresponding pH values which are between 1-2 for HCl and 3-4 for CH3COOH