Acid–alkali indicators
2 marks · NormalDescribe how you would use universal indicator to find the pH of a solution.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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Also accept: Using universal indicator paper is acceptable instead of solution
Common mistakes: Stating only 'add indicator' without mentioning colour or pH chart
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Marking points
M1 · 1 mark · States to add universal indicator (solution or paper) to the sample.
M2 · 1 mark · Explains pH is found by matching the resulting colour to a pH colour chart.
Worked solution
Add a few drops of universal indicator solution to the sample (or dip universal indicator paper in the solution). Observe the colour change. Compare the colour with a pH colour chart to determine the pH value.