Coffee has an acidic pH - red with litmus paper.
Coffee is generally acidic, thus the blue litmus paper will turn red. However, the pH of coffee can vary depending on the kind. Dark roasted coffees tend to be more alkaline and the blue litmus paper may stay blue when dipped.
When dipped in coffee, pH paper will change color based on the acidity or alkalinity of the coffee. If the coffee is acidic, the pH paper will turn a different color than if it is alkaline. This color change indicates the pH level of the coffee.
Litmus paper would turn red if apricot juice, which is acidic, was dropped on it. This is because litmus paper turns red in the presence of an acid.
Red color in acidic solutions and blue color in basic solutions.
In a neutral solution litmus has a purple color.
The color of litmus paper in acidic solutions is red.
i think purple Acid does not change the color of red litmus paper.
Aneline is basic,so litmus color is changed into blue
I believe, that acid makes blue litmus paper turn red.
the red litmus paper turns to blue
The red litmus paper dipped into household ammonia will turn blue. This is because ammonia is a base and reacts with the acidic red litmus paper, causing it to change color to blue.
Acid: Red litmus