Question

When does the color of blue litmus turn red?

Answer 1

Litmus paper:

• Paper known as "Litmus" changes color when exposed to an acidic or basic solution.
• It indicates whether a solution is basic or acidic.
• Blue litmus turns red when exposed to an acidic solution; in a basic solution, the red litmus turns blue.

Color change:

• While the red litmus paper becomes blue under basic or alkaline circumstances across the pH range of 4.5-8.3 at 25^o C, the blue litmus paper turns when the solution is acidic.
• Purple-colored Litmus paper is neutral.