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Question 21 (4 marks) (a) Outline a suitable method to prepare a natural indicator - HSC - SSCE Chemistry - Question 21 - 2015 - Paper 1
Question 21
Question 21 (4 marks) (a) Outline a suitable method to prepare a natural indicator. .................................................................................. show full transcript
Worked Solution & Example Answer:Question 21 (4 marks) (a) Outline a suitable method to prepare a natural indicator - HSC - SSCE Chemistry - Question 21 - 2015 - Paper 1
Step 1
Outline a suitable method to prepare a natural indicator.
Answer
To prepare a natural indicator, follow these steps:
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Collect Plant Material: Begin by collecting a suitable colored plant material, such as red cabbage, which is known for its acidic and basic solution color changes.
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Prepare the Plant Material: Cut the colored parts into small pieces to maximize surface area for extraction.
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Boiling Process: Place the small pieces in a beaker filled with water. Boil the mixture until the water turns deeply colored, indicating the extraction of the pigments.
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Cooling and Decanting: Remove the beaker from heat and allow the mixture to cool. After it has cooled, decant the liquid into a separate container, ensuring that the solid plant material is left behind.
Step 2
How could a natural indicator be tested?
Answer
To test a natural indicator, you can perform the following:
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Prepare Test Tubes: Take several test tubes and fill them with known acidic and basic solutions, such as vinegar (acid) and baking soda solution (base).
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Add the Indicator: Add a few drops of the prepared natural indicator to each test tube containing the solutions.
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Observe Color Changes: Record the color changes that occur in each test tube, noting how the indicator reacts to different pH levels.