In a basic solution, what color does litmus paper turn?

In a basic solution, what color does litmus paper turn?

• A. Blue
• B. Red
• C. Purple
• D. Colorless

Answer: (A)

Litmus paper shows pH through color changes because it’s an acid–base indicator. In a basic (alkaline) solution, the environment has a high pH. Red litmus paper reacts to bases by turning blue, signaling basicity. Blue litmus paper, however, stays blue in basic conditions. So the observed color is blue, reflecting the basic nature of the solution. For example, ammonia in water is basic and would turn red litmus blue.

Litmus paper shows pH through color changes because it’s an acid–base indicator. In a basic (alkaline) solution, the environment has a high pH. Red litmus paper reacts to bases by turning blue, signaling basicity. Blue litmus paper, however, stays blue in basic conditions. So the observed color is blue, reflecting the basic nature of the solution. For example, ammonia in water is basic and would turn red litmus blue.