Homemade indicators

The nature of the chemical reaction, as is well known, mostly depends on the acidity of the medium. The behavior of substances also depends on this property. Therefore, chemical laboratories use indicators for the determination of certain substances. Indicators can not always be bought, then we will try to prepare homemade indicators. The starting material will be plants: many flowers, fruits, berries, leaves and roots contain colored substances that can change their color in response to this or that effect. Getting into the acidic or alkaline environment, they visually signal us about it.

Indicators can not always be bought, then we will try to prepare homemade indicators

In summer, you can collect vegetable "raw materials" in the forest, in the field, in the garden or in the garden. Take bright flowers, for example, iris, dark tulips and roses, pansies, mallow; type raspberries, blackberries, blueberries, blueberries; stock up several sheets of red cabbage and young beets.

Since solutions of homemade indicators are obtained by boiling, they, naturally, quickly deteriorate. Therefore, homemade indicators should be prepared immediately before the experiment. Take a little stock of raw materials (the exact amount does not matter), put in a test tube, pour water, put on a water bath and heat until the solution has colored. Prepared in this way homemade indicators after cooling, filter and pour into a previously prepared clean bottle with a label.

To provide yourself with self-made indicators for the whole year, dry the summer petals and berries, arrange them in separate boxes, and then, as mentioned above, prepare from them broths, separately from each plant.

To find out which decoction serves as an indicator for this or that environment and how its color changes, it is necessary to conduct a test. Take a few drops of the homemade indicator with a pipette and add them alternately to a sour or alkaline solution. The acidic solution can be table vinegar, and alkaline solution of washing soda, sodium carbonate. For example, if you add a bright blue broth from the flowers of iris to them, then under the influence of vinegar it will turn red solution, and soda - green-blue. The results of all these experiments should be carefully recorded, preferably in a table.

Homemade indicators can be prepared not only from leaves and berries. To change the acidity, some juices and compotes are clearly reacting with a change in color. To fulfill the role of a homemade indicator can be ordinary borsch. Mistresses have noticed this for a long time. To borsch was bright red, a little acetic or citric acid is added to it before the end of cooking. The color changes literally before our eyes.

The phenolphthalein indicator is widely used in laboratories. Prepare it from pharmacy tablets of the same name. One or two tablets are rubbed and dissolved in about 10 ml of vodka. In any case, the tablets will not dissolve completely, because in addition to the basic substance, phenolphthalein, they have a filler - talc or chalk. Filter the resulting solution through blotting paper and pour into a clean bottle. This colorless solution does not deteriorate over time. It is useful for determining the alkaline environment: in it, it instantly turns red. For testing, add a drop of phenolphthalein to the solution of washing soda.

Let's talk again about vegetable homemade indicators. Once upon a time it was fashionable to write invitations on flower petals. Wrote them depending on the flower and the desired color of the inscription with an acid or alkali solution, using a thin pen or pointed stick. If you want, try to write this way, but choose petals and solutions for writing yourself. Keep in mind that the solution should not be too concentrated, otherwise the delicate petal may be damaged.