What is the color of litmus in alkaline solutions?

In alkaline solutions, litmus paper turns blue. This is due to the presence of hydroxide ions (OH-) in alkaline solutions, which causes a shift in the pH level. Litmus is a pH indicator that changes color at certain pH values; it is red in acidic conditions (pH below 7) and blue in basic or alkaline conditions (pH above 7). When exposed to an alkaline environment, the chemical structure of the litmus dye changes, resulting in the blue coloration. This property is utilized in many laboratory and educational settings to quickly assess the acidity or alkalinity of a solution.