Litmus paper is chemically treated with litmus infusion
paper. It is used to determine the degree of acidity or alkalinity of a medium. Before paper was impregnated with litmus, it was used separately as an indicator and as a chemical reagent. Litmus was first used as an indicator by the Spanish alchemist Arnaldo de Vilanova around 1300. This substance is of natural origin, it is obtained from lichens.
Litmus paper is an acid-base indicator that turns red in an acidic environment and blue in an alkaline environment. Depending on the color intensity, using a special scale, determine the pH of the medium. Hydrogen index or pH is a quantitative measure for determining the ratio of H+ and OH- ions in water, which were formed during the dissociation of water. At room temperature in a neutral solution pH=7, in an acidic pH 7.
Litmus paper is used in practice in a rather easy way: you need to take it for one
end and lower the other into the liquid medium. No need to deeply lower the paper into the liquid. The result appears immediately: the edge lowered into the medium either changes its color or does not. Then this paper is compared with the standard values, which are marked in the form of a scale on the tube or package in which the indicator was located. Litmus paper is considered a universal indicator, because. with it, you can determine the degree of both acidity and alkalinity of the environment.
This indicator can be made at home, while spending a minimum of money and time. To do this, you need red, blue or purple cabbage, filter paper or plain white paper. Cabbage should be grated on a fine grater, boil for 30-35 minutes, and then gently strain and squeeze. The cabbage itself will not be needed in the future, and in the resulting broth you need to put strips cut from paper. After the paper is soaked, take it out and dry it. Store such paper in a dry container, away from sunlight. When using such a home-made indicator, it must be taken into account that it gives a slightly larger measurement error than the factory one.
Litmus test thanks to ease of use and versatility in
in relation to the determination of pH has found wide application not only during chemical experiments in educational institutions and clinical laboratories, but also in everyday life. So, any person can easily, using litmus paper, determine the pH of any biological fluid, solutions, mixtures - saliva, urine, breast milk, water, soap, etc. pH-biological parametersfluids must be self-monitored in some diseases. Also, litmus paper is actively used by flower growers at home to determine the degree of acidity and alkalinity of the soil. You can use it to determine the pH of cosmetics, in particular those used for skin care, because. ideally they should be neutral.
