LITMUS

Chemical Properties

blue powder

Definition

litmus: A water-soluble dye extractedfrom certain lichens. It turnsred under acid conditions and blueunder alkaline conditions, the colourchange occurring over the pH range4.5-8.3 (at 25°C). It is not suitable fortitrations because of the wide rangeover which the colour changes, but is used as a rough indicator of acidityor alkalinity, both in solution and aslitmus paper (absorbent paper soakedin litmus solution).

Definition

A natural pigment that changes color when in contact with acids and alkalis; above a pH of 8.3 it is blue and below a pH of 4.5 it is red. Thus it gives a rough indication of the acidity or basicity of a solution; because of its rather broad range of color change it is not used for precise work. Litmus is used both in solution and as litmus paper.