Aim: To make acid-base indicators using everyday substances.

Equipment: Red cabbage, tea, beetroot, turmeric, cranberry juice, a beaker, water, tripod, Bunsen burner, gauze mat, 1.0 moI L1.0 moI L-1 HCI 1.0 mol L-1 NaOH. 


Task One

For Cabbage and Beetroot 

Chop the cabbage into small pieces until you have enough to fill 2 cups.

Place the cabbage in a large beaker and add water to cover the cabbage.

Boil over a Bunsen burner for at least ten minutes for the colour to leach out of the cabbage.

Filter out the plant material to obtain a red-purple-bluish coloured liquid. This liquid is at about pH 7. (The exact colour you get depends on the pH of the water.)

Place in a small beaker and leave to one side.

Repeat this method for the beetroot.



For The Tea

Put 100 ml of water into a beaker and boil.

Turn off the Bunsen burner and put three tea bags in the beaker.

Remove the tea bags when the tea is very strong.

Place in a small beaker and leave to one side.



For The Cranberry Juice

Pour into a beaker and leave to one side.



For the Turmeric 

Mix 1 teaspoon turmeric in 100 mL cup of alcohol.

Place in a small beaker and leave to one side.