By Guan Foo
Learning Objectives: To understand which indicator to use for the different types of acid-base titrations.
Interactive Prompt:
Grade level: Junior College 1

Student readiness level: Mixed Abilities

The graph visualisation focuses on: Using titration curves to explore the suitability of indicators to determine colour change at end-point.

 

The objective of the visualisation is to: Help students understand which indicator to be used is dependent on the type of acid-base titration (e.g. strong acid-strong base, strong acid-weak base, weak acid-strong base, weak acid-weak base). Students should be given the opportunity to see the various types of acid-base titration and from there, explore which indicators (e.g methyl orange, screened methyl orange, thymolphthalein) can be used. Thereafter, they should be given the opportunity to explain the choice of indicator.

 

While exploring the various titration curves, students should experience: Choosing an indicator and see where its working range lies on the pH scale of titration curve. The titration curve has pH as the y-axis and volume of titrant as the x-axis. Students should be given the option to define the titrant used.

 

The interface should include: Choice of indicators (methyl orange, screened methyl orange, thymolphthalein), Working range of indicators, appearance of conical flask as the titration proceeds with indicator added.