Making Indicators

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 mol L-1 NaOH.

Our options we were given to do the experiment were Cabbage - Beetroot, turmeric, Cranberry juice and tea. Out of those options, my group choose turmeric, Beetroot, and Cranberry juice. 

Method:

Cranberry - Pour the Cranberry juice into a beaker and leave it on one side.

Turmeric - Mix 1 teaspoon of turmeric in a 100 mL cup of alcohol, then place it in a small beaker and leave it on one side.

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 it in a small beaker and leave it on one side.

Results:

Indicator	Colour in HCI (Acid)	Colour in NaOH (alkali)
Tea	Light Brown	Brown
Cabbage	Pink	Yellow
Turmeric	Light green	Orange
Beetroot	Light green	Pink
Cranberry	Dark green	Light pink

Discussion - We used an indicator, which helped us see if the colour changed or if they were colour was HCI (Acid) or NaOH (base - alkali). We have learned that both Acid and base are both different, and that they change different colours when they are reacted with liquid. For an example, Acid was poured into water, then the colour of the water reacts with the Acid and the colour changes, and the same thing would happen if base was poured into the water.

Conclusion - This experiment was an successes and we got the correct result that we were looking for. What we would do differently next time is to not get the colours mixed up, but put them in the correct order next time.