Question

Collect different types of flowers annd prepare their natural indicators with the help of filter paper?s

Answer 1

CHE Pack 6 – Preparation of Natural Indicators
3
Produced by the Chemistry Group, UCC, as part of DelPHE-funded collaboration between University of Cape
Coast and The Open University, UK
A. Teacher’s Guide
Preparation of test solutions
 Lemon juice: squeeze out and filter the juice from the lemon fruit.
 0.1M Hydrochloric acid (HCl) solution: measure 1.7ml of concentrated HCl into 100ml of
distilled water.
 Dissolve 20g of Baking soda in 50ml distilled water
 0.1M NaOH solution (NaOH is available as lye from the market and from soap makers;
dissolve 4.0g NaOH in enough distilled water to make 100ml of solution)
 Distilled water
Sample collection and treatment
Collect enough samples of colored flowers
For the sake of time, prepare Waakye leaf extract for the students
Sample Assessment Questions
1. What caused the colour changes in each of the solutions? (KN)
2. Outline the steps involved in the extraction of indicator from the plant. (KN)
3. How do indicators from the different flowers differ from each other?
4. Explain what caused the colour changes in each of the solutions (KN)
5. Mention the principles involved in extracting natural indicators from natural sources (C)
6. Describe some everyday uses of indicators including the testing of soil acidity/basicity
(KS)

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