What is the hypothesis in the red cabbage experiment?
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What is the hypothesis in the red cabbage experiment?
This is a sample hypothesis: Since cabbage extract will change color in different pH, we can use it to make pH indicators for the range of pH that color change of cabbage extract is visually detectable. Among household items, vinegar and lemon juice are acidic. Soaps and detergents are alkaline.
Why does cabbage work as a pH indicator?
Discussion: Red cabbage is useful as a pH indicator because the leaves contain a pigment molecule from the family of anthocyanins (shown below) which are responsible for many of the red/purple/blue colors observed in fruits and vegetables. As the solution becomes more acidic a red color results.
How is red cabbage used as an indicator?
Procedure
- Chop the cabbage into small pieces until you have about 2 cups of chopped cabbage.
- Filter out the plant material to obtain a red-purple-bluish colored liquid.
- Pour about 50–100 mL of your red cabbage indicator into each 250 mL beaker.
- Add various household solutions to your indicator until it changes color.
What substance does purple cabbage indicator actually test for?
Background Information for the Teacher: Red cabbage juice can tell if a substance is an acid or a base when added to it. It is an indicator. If the substance is an acid when the red cabbage juice (purple in color) is added it will turn a shade of red.
What does pH measure?
pH is a measure of how acidic/basic water is. The range goes from 0 – 14, with 7 being neutral. pHs of less than 7 indicate acidity, whereas a pH of greater than 7 indicates a base. pH is really a measure of the relative amount of free hydrogen and hydroxyl ions in the water.
What is the pH of cabbage?
Figure 6.
| pH | Color |
|---|---|
| 6 | Violet |
| 8 | Blue |
| 10 | Blue-green |
| 12 | Greenish-yellow |
Is cabbage alkaline or acidic?
Fresh vegetables Like fruits, vegetables are also considered alkalizing and can help reduce acid levels in the body. Here is the PRAL for a 3.5-ounce (100-gram) serving of some common vegetables ( 4 ): white cabbage (raw): -1.5.
Is red cabbage natural indicator?
Red cabbage juice contains a natural pH indicator that changes colors depending on the acidity of the solution. The pigment in red cabbage that causes the red color change is called flavin (an anthocyanin).
What colour is the cabbage indicator when alkali?
red
Why does red cabbage make a good indicator? Red cabbage contains a chemical called anthocyanin. This changes colour depending on the acidity of its environment. It turns a pink/red colour in the presence of an acid, is purple when neutral and when added to an alkaline substance turns blue or green.
How does cabbage juice measure pH?
To use your pH indicator, pour about 2 teaspoons (10 ml) of each test substance into a separate Dixie cup. To each cup, add approximately 1/2 teaspoon (2 ml) of cabbage juice indicator. Now watch for the color changes! If the substance is an acid (i.e. lemon juice), the indicator should turn bright pink.
How does pH sensor works?
The combination or pH electrode measures the difference in potentials between the two sides in the glass electrode. As the electrode is immersed in the test solution the glass bulb senses the hydrogen ions as a millivolts (mV) due to the positive charge of the hydrogen ions.