Litmus Red Indicator Papers 10 Booklets Qualigens

Qualigens litmus red indicator paper is a natural pH indicator that can be used to determine if a solution is acidic or basic: 

	Qualigens litmus red indicator paper
Color change	Red litmus paper turns blue in basic or alkaline solutions
pH range	Changes color from red (below 4.5) to blue (above pH 8.3)
Features	Eco-friendly, easy to use, and highly accurate

Litmus paper is made by treating filter paper with a natural dye extracted from lichen. It's the oldest form of pH indicator and is still commonly used, even though other pH papers are made with synthetic indicator dyes. 

The color change in litmus paper occurs when the pigment in the paper reacts with H+ ions in acids. This changes the bonds in the pigment, causing them to reflect a longer wavelength of light, which appears red to human eyes. 
Other pH test papers are available that have distinct colors for each pH from 1 to 14. However, these papers don't provide precise results because they don't have a specific numerical pH value.