The color of the blue litmus paper turning into red tells us that the solution of the compound is acidic in nature.
The color of the red litmus paper turning into blue tells us that the solution of the compound is basic in nature.
Explanation:
Litmus paper is paper treated with a mixture of natural dyes obtained from lichens. This makes the paper purple in neutral conditions (pH = 7), red in acidic conditions (pH < 7), and blue in basic (alkaline) conditions (pH > 7). It is used to determine whether a solution is acidic or basic, but can't measure the pH.
