PRAC REPORT: WHAT IF PLANTS WERE USED TO CREATE AN INDICATOR
Date: 17 October 2018
Author: Yash Sharma, Thidas Gammanpila, Anirudh Sridhar
Aim: To observe the colour changes which occur in various substances when they come in contact with red cabbage indicator. Based on the results determine whether the substances are acidic, basic or neutral.
Hypothesis: Bleach will produce a yellow solution after being reacted with the red cabbage indicator, also Bleach will be the most basic substance as it has a nature of a high ion concentration. Hydrochloric acid will produce a dark red colour solution when coming in contact with the red cabbage indicator. Hydrochloric acid will also be the most acidic substance because it having the highest *H ion concentration.
1. Red cabbage Flavin indicator 50mL
2. Hydrochloric acid (HCl) 100mL
3. Phosphoric acid (H3PO4) 100 mL
4. Bi-carb soda (baking soda) 100 mL
5. Sodium hydroxide(NaOH)100mL
6. Vinegar 100 mL
10.Lemonade 100 mL
11.Ammonia solution (NH4OH)
12.Sugar solution 100 mL
14.Cream cleanser 100 mL
15.Milk 100 mL
18.Test tube x1
20.Test tube rack x1
21.pH level chart x1
22.Pen and paper for recording the results
1. First obtained 50 ml of red cabbage Flavin in a beaker.
2. Then, acquired a test tube and a pipette.
3. A test tube was safely placed in the test tube rack.
4. A few drops of hydrochloric acid were added to the test tube.
5. 5 drops of Flavin was added to the test tube.
6. The colour change which occurred was recorded.
7. Later, the substance was identified as an acid, base or neutral based on the colour change.
8. The pH level chart was used to identify the pH level of the substance.
9. Photographs were taken using an iPad.
10. Steps 4-9 were repeated.
11. Steps 6-9 were repeated for non-liquid substances.
Substance Colour change pH level Acid, base or
Hydrochloric acid (HCl) Dark red 2 Acid
Phosphoric acid (H3PO4) Pink 3 Acid
Bi-carb soda Turquoise 9.5 Base
Cream cleanser Dark green 10 Base INCLUDEPICTURE “/var/folders/31/514c6_711q5_w21wq5d2c7g40000gn/T/com.microsoft.Word/WebArchiveCopyPasteTempFiles/page5image37303088” * MERGEFORMATINET
Milk Light purple 6 Neutral INCLUDEPICTURE “/var/folders/31/514c6_711q5_w21wq5d2c7g40000gn/T/com.microsoft.Word/WebArchiveCopyPasteTempFiles/page5image37292272” * MERGEFORMATINET
Detergent Light purple 6 Neutral INCLUDEPICTURE “/var/folders/31/514c6_711q5_w21wq5d2c7g40000gn/T/com.microsoft.Word/WebArchiveCopyPasteTempFiles/page5image37295808” * MERGEFORMATINET
Discussion: Red cabbage Flavin was used as an indicator to find out whether various substances are acid, bases or neutral. Colour changes occurred when substances came in contact with red cabbage indicator. Acids were mostly red, bases were yellow and neutral substances changed to purple when they came in contact with the red cabbage indicator. According to our observations, hydrochloric acid was the most acidic substance and bleach was the most basic substance. This supported the hypothesis.
Acidic substances produced red colour when they came in contact with the red cabbage indicator. This is because acids are substances which release *H ion when they come in contact with another substance. Acids also show a red colour solution when they come in contact with an indicator. During this experiment, Hydrochloric acid, lemonade, vinegar, lemon juice and hand wash were classified as acidic substances because they turned red during the experiment.
Bases substances produced red colour when they reacted with the red cabbage indicator. This is because bases are substances which release OH ions when they come in contact with other substances. During this experiment, Bi carbonate soda, bleach, ammonia solution, sodium hydroxide, cream cleaner was categorised as basic substances. This is because they changed their colour to yellow when they reacted with red cabbage indicator.
Neutral substances are neither base or acids. Some of their properties are having sweet or salty or no taste. Toothpaste, sugar solution, milk and detergent were classified as neutral substances because they produced a purple colour solution when they reacted with red cabbage indicator.
It was ensured that this is a fair test and the results produced were not biased. Thus, obtaining the correct amount of red cabbage indicator was very important but also hard. For unbiased results this step of obtaining the correct amount of red cabbage indicator was performed several times. Thus, it is believed that the results were unbiased and accurate.
Conclusion: In conclusion, the colours which were produced by various substance when they came in contact with red cabbage indicator was observed. Thus, the hypothesis was supported.