It is easy to explain what a litmus is - a chemical substance of natural origin, with the help of which the acid-base level of a water or solution is determined. Once in the acidic environment, the litmus turns red, in the alkaline - it acquires a blue tint, in the neutral - violet. This is the most common indicator that is used in industry and can be useful at home.
The origin and receipt of litmus
The substance is extracted industrially from several species of lichens growing in Sweden, Norway, the USA, South America, Angola, Madagascar, the Canary and Azores, and some other places. Lacmus and its properties were discovered around 1300. For a long time, the extraction of material was monopolized, the method of obtaining was carefully hidden. First it was mined by the following method:
- the raw materials were crushed;
- they were soaked in a soda-ammonia solution for up to 21 days, constantly stirring the mass, in some cases, urine was used instead of chemicals;
- when the mass turned from red to blue, the precipitate was filtered;
- the blue substance was thoroughly dried and ground into powder;
- then the drug was subjected to alcohol extraction;
- combined with gypsum or chalk, pressed, and as a result, finished blocks of litmus were obtained, which easily crumbled for further use.
In the XVIII century, chemists began to use an aqueous solution of lime and ammonium carbonate instead of soda-ammonia.
Litmus paper
Indicator litmus paper is a piece saturated with a chemical substance. Available in separate strips or in rolls. This format is the most common.
Using litmus paper is very easy. It is enough to tear off one strip and immerse in the liquid that needs to be examined. Almost immediately, the paper will acquire that color shade that corresponds to the acid-base level of the test substance. This is what litmus is in action.
Scope of application
It is usually used to determine the level of PH in industry and at home. It is used:
- in the chemical industry to identify the environment during research;
- in the food industry to recognize the acidity level of drinks and drinking water;
- in cosmetology in the manufacture of creams, tonics and other skin care products;
- in agriculture to determine the composition of the soil;
- in medicine for analysis of urine, saliva, other fluids and secretions;
- for determination of acid-base water level in pools, heating boilers.
In everyday life, it will also be useful to know what litmus is and how to use it. Lovers of plants, gardeners and gardeners with the help of a litmus test will be able to determine the pH level of the soil and home-made fertilizers. The optimum acid-base soil level is 6-6.5 units for most plants. If the indicators deviate from the norm, plants slow down growth, discard foliage or stop flowering for no apparent reason.
Aquarium fish are also sensitive to the pH level of water in the aquarium. The optimal balance, which is suitable for most species of fish and plants, is 6.3-7 units. If the indicators exceed the mark of 7, the plants may die, and if they fall below 6, the fish may not survive.
Both store-based and home-made cosmetics should have a neutral pH of about 5.5. To verify this, just dip the litmus test into a liquid or suspension.
In some diseases, it is important to control the acid-base balance of blood or urine. To do this, regularly conduct tests with litmus paper at home. In this case, the attending physician will explain what a litmus is and how often it should be used.
The figurative meaning of the word "litmus"
This chemical term is often used in a figurative sense. Here is what “litmus” means: something that allows you to find out the state of an object, phenomenon, event, system. For example: "his gift for March 8 was the litmus of our relationship."