Red Cabbage Indicator - American Chemical Society (2024)

FAQs

What is the red cabbage indicator in ACS? ›

Red cabbage contains a chemical called anthocyanin. This pigment is a natural acid-base indicator. It is blue in neutral substances, like plain water. When an acid like lemon juice gets in the water, a reaction makes the indicator molecule change shape and it looks pink.

Red cabbage contains a water-soluble pigment called anthocyanin that changes color when it is mixed with an acid or a base. The pigment turns red in acidic environments with a pH less than 7 and the pigment turns bluish-green in alkaline (basic), environments with a pH greater than 7.

Alternatively, you can place about 2 cups of cabbage in a blender, cover it with boiling water, and blend it. Filter out the plant material to obtain a red-purple-bluish colored liquid. This liquid is at about pH 7. The exact color you get depends on the pH of the water.

Unused red cabbage indicator solution may be stored in a stoppered flask and refrigerated for up to one week.

The dishwasher soap mixture should turn a vivid blue-green because dishwasher soap is very basic, or alkaline.)

The cabbage juice is called an indicator because it can tell you the pH of a solution based on the color that it changes. The vinegar will turn the cabbage juice red because it is an acid (acetic acid). The baking soda will turn the cabbage juice greenish-yellow because it is a base (sodium bicarbonate).

Cabbage water has excellent detoxifying properties due to its high content of antioxidants, and phytochemicals. These compounds help eliminate harmful toxins from the body, reducing the burden on your liver, and promoting a healthy complexion.

The red cabbage solution will turn a colourless solution of bleach to light yellow which indicate the bleach is alkaline or basic. This happens because bleach is alkaline.

CONCLUSION. Red cabbage juice will change its colour when an acidic or alkali solution added into it. For example, when hydrochloric acid is added, the purple coloured red cabbage juice change to red colour and green colour when added ammonia. This shows that red cabbage can act as a natural indicator.

Add the cabbage and one cup (or 200 mL) of water into the blender. Blend the water and cabbage and then strain the mixture, saving the liquid. Adjust the amount of water accordingly. You will need roughly 5 mL of indicator per test.

Is red cabbage acidic or alkaline? ›

Red Cabbage Juice Indicator

Acidic solutions turn the anthocyanin a reddish hue, neutral purplish in color, and when alkaline, a greenish/yellow. Cabbage juice will be purple, which means it is neutral, or around a 7.0 on the pH scale.

Carefully pour the remaining liquid into a plastic or glass container. The liquid is now ready to be used as a pH indicator solution. Keep refrigerated until use. Can be stored in the refrigerator for up to one week.

Ans: Red cabbage is a good indicator, but it has its disadvantages which are as follows: It is slower than litmus paper, it contaminates the solution, it does not tell about the acidic or basic strength, it requires more solutions than litmus paper, and if the solution is dark, the colour change is not visible.

Red cabbage indicator is a purple-coloured solution that is used to test whether substances are acid or base. Red cabbage that is often found in homes can be used to prepare a solution that acts as a pH indicator.

The pigment turns red in acidic environments with a pH less than 7 and the pigment turns bluish-green in alkaline (basic) environments with a pH greater than 7. Red cabbage is just one of many indicators that are available to scientists.

The colour in red cabbage is a pigment called an anthocyanin. Red cabbage is an olfactory indicator of acid.

Substances such as lemon juice and vinegar turn the cabbage juice red because they are acidic. Ammonia turns the cabbage juice into a blue/green color because it is a base, a material that tastes bitter and makes an acid neutral.