FA1 PROJECT WORK CLASS X

Title of the Project: 
Make an indicator using hibiscus petals.

Purpose of the project: To make an indicator with natural resources to test acid and bases. 

Hypothesis: Indicators are substances whose solutions change colour due to changes in pH. These are called acid-base indicators. Some petals of the flowers contain dye molecules which are weak acids and bases. These can be used as acid-base indicators. 

Materials: hibiscus flowers, container, surgical spirit, mortar, pestle, hydrochloric acid, sodium hydroxide. 

Procedure:  

1) Cut approximately 10 mature hibiscus flowers. 

2) Remove the stigma, and detach the leaves, so as to have only the red petals remaining. 

 

3) Put them in a container, and pour approximately 6ml of ethanol or surgical spirit; the latter works best. 

4) Crush the petals using an appropriate implement, such as a mortar and pestle. Crush until all of the liquid has been extracted from the petals. 

5) Filter the solution, and you have the reddish indicator ready. 

6) Take hydrochloric acid in a beaker and add the hibiscus indicator. it turns in to highlighted red colour. 

7) Take Sodium hydroxide in a beaker and add the hibiscus indicator. It turns in to dark green (almost black) colour. 

Learning outcome: 

we prepare the natural indicator with hibiscus flowers to know the acidity and basicity of the solutions. 

Precautions: Take care with hydrochloric acid while doing the testing of acidic property. 

Interpretation of the student: 

After completion of the project we know the acidic and basic properties of the solutions with the help of indicators.

Conclusion: 

After completion of this project we conclude that indicators are substances whose solutions change colour due to changes in pH. These are called acid-base indicators. Some petals of the flowers contain dye molecules which are weak acids and bases. These can be used as acid-base indicators.