ChemLab #31 - Home-made Indicator
Date of Lab:   Score:
Lab Group Members:   This is an individual lab to be done AT HOME.
Problem Statement: Make an acid-base indicator at home.
Hypothesis:
 
Research References:   Lab Key
Experimental Design Observations
Procedure:
     
  1. Finely chop half a head of red cabbage.
     
  2. Carefully boil the chopped cabbage in about a liter of water for 5 minutes.
     
  3. Remove from heat and let stand until completely cool.
     
  4. Strain the liquid, and throw away the cabbage.
     
  5. The liquid should be a dark reddish-purple color. This is the organic compound that acts as an acid-base indicator.
 
Test of your indicator by adding a few drops to:
     
  • A colorless neutral solution, like water. (Only de-ionized water is exactly neutral, but most tapwater is close enough for this test.)
     
  • A colorless base solution, like household ammonia.
     
  • A colorless acid solution, like distilled vinegar.
 
To make 100% on this lab, bring the following to class:
     
  • A small amount of your indicator.
     
  • This lab report guide showing the results of your indicator test.