lakmuspaberit

Lakmuspaberit, often referred to as litmus paper in English, is a simple yet crucial tool used in chemistry to determine the acidity or alkalinity of a solution. It is made by impregnating filter paper with a mixture of natural dyes derived from lichens, most notably Roccella tinctoria. These dyes undergo a color change when exposed to varying pH levels.

The principle behind litmus paper's function is its sensitivity to hydrogen ions. In acidic solutions, which have a high concentration of hydrogen ions, litmus paper turns red. Conversely, in alkaline or basic solutions, where hydrogen ions are scarce and hydroxide ions are abundant, the paper turns blue. If a solution is neutral, meaning it has an equal concentration of hydrogen and hydroxide ions, the litmus paper will remain its original purple color.

Litmus paper is typically sold in two forms: red litmus paper and blue litmus paper. Red litmus paper turns blue in alkaline solutions and stays red in acidic or neutral solutions. Blue litmus paper turns red in acidic solutions and stays blue in alkaline or neutral solutions. This dual nature allows for a quick qualitative assessment without the need for precise numerical pH measurements. While not as accurate as pH meters or universal indicator solutions, litmus paper remains a popular choice for educational demonstrations and preliminary testing due to its ease of use and low cost.