1. Acids and Alkali
Alex Cheong
1P404

2. Contents Introduction Objective Hypothesis Materials Procedure Results
Conclusion

3. Introduction
Acids are sour and form hydrogen gas when they react with metals
Citric acid, acetic acid
Alkali are bitter and slippery. Most are water soluble
Sodium hydroxide, magnesium hydroxide
pH scale is a way to measure the strength of an acidic or alkaline solution
Acids have a pH of 0-7, while alkali have a pH of 7-14
Water’s pH level is 7, and is a neutral solution

4. Objective Easily identify acids and alkali
solutions in our everyday substances using the juice of the red cabbage

5. Hypothesis
The juice of the red cabbage can be used to identify acids and alkali

6. Materials Red cabbage Toilet bleach Father Lemon juice Baking soda
Salt
Vinegar
Sugar

7. Procedure Peel some red cabbage leaves
Boil the cabbage leaves for 15 minutes
Transfer the liquid into a bottle
Pour some into the test tube
Add one of the everyday substances into the test tube
Observe the colour of the indicator
Write down the results in a table

8. Results Substance Added Colour After Adding Vinegar Reddish Lemon
Pinkish
Baking Soda
Green

9. Results (continued) Substance Added Colour After Adding Toilet Bleach
Yellow
Sugar
No Difference
Salt

10. Conclusions Red cabbage juice can be used as a
indicator solution to identify acids and
alkali.
The red cabbage has a pigment called anthocyanin in it’s juice which colour depends on the pH of the solution
If the substance is a …
acid, then the solution will turn pink to red
alkali, then the solution will turn blue, green to yellow
From the results, we can see that toilet bleach is a strong alkaline.