What is a litmus solution? How is it obtained?

Litmus solution is a purple, natural indicator dye extracted from lichens (simple thallophyte organisms). It’s prepared by grinding/crushing lichens to obtain the dye, then dissolving it in distilled water.

Use: to test whether a solution is acidic or basic.

• In an acidic medium: litmus turns red.
• In a basic (alkaline) medium: litmus turns blue.
• In a neutral solution: no color change.