OC18 Use litmus, a natural indicator & universal indicator to test a variety of solutions,

and classify these as acidic, basic or neutral


Test tile, beakers, water, droppers, list of substances to test for acid and bases, Red Cabbage, litmus papers, universal indicator papers

Method & Diagram

  1. Mix up some different solutions that you want to test.
  2. Assign these solutions different locations on a test tile
  3. In your notebook, draw and label out the test tile and the locations of each substance.
  4. Get 1 test paper of Blue Litmus, Red Litmus and Universal Indicator paper for each sample.
  5. In each substance dip the litmus papers in, note in a table the colour each litmus paper turns.
  6. In each substance dip the Universal Indicator paper, note the colour & compare to the coloured 'swatches' and make a call of the pH number to be assigned to each substance.
  7. Finally using a dropper, add 1/2 drops of the natural indicator to each substance and note the colour the solution ends up



If both litmus turn Red → Acid,

Blue → Base,

If the pH < 7 → Acid,

pH = 7 → neutral,

if pH > 7 → Base

Complete the following a number of times

__________ is a __________ and has a pH of ___ .

I know this because _________ turned _______ and the Universal indicator had a ______colour corresponding to a pH of ___


Kawah Ijen volcano Crater lake 1km across, and its water has pH of 0.5