Acid-Base Titration Colour Change

In the picture

1. 1Burette scale at the meniscus: the volume of solution delivered
2. 2Stopcock: controls the flow of solution from the burette
3. 3Conical flask with pale pink liquid: the indicator has changed colour
4. 4White tile: provides a clear background for judging the colour

Examples

• Using phenolphthalein to find the concentration of vinegar by titrating it with sodium hydroxide.
• Checking the acidity of a fruit juice sample by adding a base until the indicator turns pink.

Quiz: Acid-Base Titration Colour Change (Age 18)

1. 1

   During an acid-base titration, what does the indicator colour change indicate?

   • The halfway point, where half of the titrant has been added
   • The end point, which is chosen to be very close to the equivalence point
   • The exact equivalence point, even if the indicator changes slightly before or after it
2. 2

   In a titration calculation, what must be used together with the volume of titrant added to find the unknown concentration?

   • The titrant’s known concentration and the reaction stoichiometry
   • The time taken for the colour change and the room temperature
   • The indicator colour and the size of the conical flask
3. 3

   What is the function of the stopcock in the titration setup?

   • It measures the volume of solution delivered from the burette
   • It provides a clear background for judging the colour change
   • It controls the flow of solution from the burette

The answers, each with its explanation, are in the app. This lesson has left the free week, so its quiz is part of the subscription.