Answer:

Key concepts

Chemistry

Acids

Bases

Light

Introduction

You might have done experiments with well-labeled acids and bases in school, but have you ever wondered whether a certain food or chemical around the house is an acid or a base? You can find out using a red cabbage to make an indicator solution.

When two or more ingredients are entirely dissolved in one another, you have a solution. For example, mixing salt with water creates a clear solution, even though the salt is there and the solution tastes salty. When mixed with water, whether a chemical "donates" a charged particle (called an ion) to the solution—in this case, a hydrogen ion—or "accepts" one from it determines whether it's an acidic or basic solution. An indicator changes color when exposed to such a mixture, depending on whether the solution is acidic or basic.

ADVERTISEMENT

Background

Acids are solutions that lose hydrogen ions and usually taste sour. Some very common household solutions are acids, such as citrus fruit juices and household vinegar. Bases are solutions that pull hydrogen ions out of solution and onto themselves, "accepting" them, and usually feel slippery. Bases have many practical uses. For example, "antacids" like TUMS are used to reduce the acidity in your stomach. Other bases make useful household cleaning products.

To tell if something is an acid or a base, you can use a chemical called an indicator. An indicator changes color when it encounters an acid or base. There are many different types of indicators, some that are liquids and others that are concentrated on little strips of "litmus" paper. Indicators can be extracted from many different sources, including the pigment of many plants. For example, red cabbages contain an indicator pigment molecule called flavin, which is a type of molecule called an anthocyanin. Very acidic solutions will turn an anthocyanin red whereas neutral solutions will make it purplish and basic solutions will turn it greenish-yellow. Consequently, the color an anthocyanin solution turns can be used to determine a solution's pH—a measure of how basic or acidic a solution is.

Materials

•    A small red cabbage

•    Pot of boiling water

•    Strainer

•    Two large bowls or pots

•    Grater

•    Tablespoon measurer

•    Large spoon (optional)

•    Three or more small, white paper cups (small, white paper drinking glasses or dishes will also work)

•    Goggles or other protective eyewear

•    Lemon or lime juice

•    Vinegar

•    Bleach-based cleaning product

•    Other foods to test, such as clear soda pop, baking soda solution, egg whites, tomatoes, cottage cheese (optional)

Preparation

•    Grate a small red cabbage. If you do not want to grate the entire cabbage, grating half of a cabbage should be enough. Put the fine, pulpy grated cabbage into a large bowl or pot.

•    Boil a pot of water. Use caution when handling the boiling water. Pour the boiling water into the bowl with the cabbage pulp until the water just covers the cabbage.

•    Leave the cabbage mixture steeping, stirring occasionally, until the liquid is room temperature. This should take at least half an hour. The liquid will become red or purplish-red in color.

•    Place a strainer over another large bowl or pot and pour the cabbage mixture through the strainer to remove the cabbage pulp. Press down on the pulp in the strainer, such as by using a large spoon, to squeeze more liquid out of the pulp.

•    In the bowl, you should now have only liquid that will either be purple or blue in color. This will be your indicator solution, which you will use to test the pH of different liquids.

•    Children should wear goggles or other protective eyewear and adults should supervise and use caution when handling bleach and vinegar, because they can irritate eyes and skin.

Procedure

•    Fill a small, white paper cup, drinking

Explanation:

pa brainliest po sana maka tulong