It's easy to explain what litmus is - a chemical substance of natural origin, which determines the acid-base level of water or solution. Litmus turns red when exposed to an acidic environment, blue when exposed to an alkaline environment, and purple when exposed to a neutral environment. This is the most common indicator used in industry and can be useful at home.
Origin and production of litmus
The substance is produced industrially from several types of lichens growing in Sweden, Norway, USA, South America, Angola, Madagascar, the Canary and Azores and some other places. Litmus and its properties were discovered around 1300. For a long time, the extraction of the material was monopolized, the method of obtaining was carefully hidden. It was first mined using the following method:
- raw materials were crushed;
- soaked in soda-ammonia solution for up to 21 days, constantly stirring the mass, in some cases instead ofchemicals used urine;
- when the mass turned from red to blue, the precipitate was filtered;
- the blue substance was thoroughly dried and ground into a powder;
- then the drug was subjected to alcohol extraction;
- combined with gypsum or chalk, pressed, and as a result, ready-made litmus blocks were obtained, which easily crumbled for further use.
In the 18th century, chemists began to use an aqueous solution of lime and ammonium carbonate instead of soda-ammonia.
Litmus paper
Indicator litmus paper is cuts impregnated with a chemical. Available as single strips or in rolls. This format is the most common.
It is very easy to use litmus paper. It is enough to tear off one strip and immerse it in the liquid to be examined. Almost immediately, the paper will take on the shade of color that corresponds to the acid-base level of the test substance. Here is litmus in action.
Scope of application
Usually used to determine the PH level 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;
- inmedicine for testing urine, saliva, other fluids and secretions;
- to determine the acid-base level of water in swimming pools, heating boilers.
In everyday life, it will also be useful to know what litmus is and how to use it. Plant lovers, flower growers and gardeners can use litmus paper to determine the pH level of the soil and homemade fertilizers. The optimal acid-base level of the soil is 6-6.5 units for most plants. If the readings deviate from the norm, the plants will slow down growth, shed their leaves or stop flowering for no apparent reason.
Aquarium fish are also sensitive to the pH level of the water in the aquarium. The optimal balance, which is suitable for most varieties of fish and plants, is 6.3-7 units. Above 7 the plants may die, and below 6 the fish may not survive.
Both store-bought and homemade cosmetics should have a neutral pH of about 5.5. To verify this, just dip a litmus test in a liquid or suspension.
In some diseases, it is important to control the acid-base balance of blood or urine. To do this, you should regularly conduct tests with litmus paper at home. In this case, the attending physician will explain what litmus is and how often it should be applied.
Figurative meaning of the word "litmus"
This chemical term is often used figuratively. That's whatmeans "litmus": something that allows you to find out the state of any object, phenomenon, event, system. For example: "The litmus of our relationship was his gift on March 8".
