Litmus paper is commonly used for determining pH levels. Its blue variety indicates acidity when it turns red, while the red variety turns blue to represent basicity. In contrast, neutral litmus paper remains unchanged regardless of acidity or basicity.

• Acidity Testing (Blue Litmus Paper): Identify acidic solutions. Paper turns red in acidic solutions and shades darker as acidity increases. Tested with multiple pH buffers, the paper is blue at pH 8 and turns to red at pH 6.5 and lower.

• Neutrality Testing (Neutral Litmus Paper): Identify solutions that are neither strongly acidic nor strongly basic. It turns red in acidic solutions (pH <7) and blue in alkaline solutions (pH >7).

• Alkalinity Testing (Red Litmus Paper): Identify alkaline or basic solutions. Test pH easily with Red Litmus paper. Strip changes to blue in alkaline solution.