Final Answer:
Litmus paper that is initially blue will turn red in the presence of a strong base. Blue litmus paper serves as an indicator of acidity and turns red under basic conditions.
Step-by-step explanation:
Litmus paper that is initially blue will turn red in the presence of a strong base. Litmus paper is a pH indicator that changes color depending on the acidity or basicity of a solution. Blue litmus paper is specifically used to test for the presence of an acid.
In the presence of a strong base, such as sodium hydroxide (NaOH) or potassium hydroxide (KOH), the base reacts with the blue litmus paper, causing it to turn red. This color change indicates the basic nature of the solution. Litmus paper serves as a simple and quick method for qualitative assessment of the pH level in a substance, with red indicating acidity and blue indicating basicity.