1. Red Litmus Paper:

- When dipped into an acidic solution, red litmus paper turns red, indicating the presence of an acid.

- The acid donates H+ ions to the litmus paper, causing it to change color.

For Testing Bases:

1. Blue Litmus Paper:

- When dipped into a basic solution, blue litmus paper turns blue, indicating the presence of a base.

- The base donates OH- ions to the litmus paper, causing it to change color.