Co-Authored By:
Asked by: Nagina Junghanns
science chemistryWhy did the phenol red turn pink?
Last Updated: 16th April, 2021
Above pH 8.2, phenol red turns a bright pink (fuchsia) color. and is orange-red. If the pH is increased (pKa = 1.2), the proton from the ketone group is lost, resulting in the yellow, negatively charged ion denoted as HPS−.
Click to see full answer.
Keeping this in view, what does phenol red indicate?
Phenol red is a water-soluble dye used as a pH indicator, changing from yellow to red over pH 6.6 to 8.0, and then turning a bright pink color above pH 8.1. As such, phenol red can be used as a pH indicator dye in various medical and cell biology tests.
Similarly, what does it mean when phenol red turns yellow? Phenol red is a pH indicator that is yellow at a pH below 6.8 and red at a pH above 7.4 with varying shades from yellow to red between those pH levels. If the indicator has turned yellow in the bottle this means it has become contaminated with something that has made the pH more acidic and brought the pH below 6.8.
Subsequently, one may also ask, what causes color change in phenol red?
The phenol red changes color when you blow into it, because you are introducing carbon dioxide to the mix. Phenol red changes to yellow in a pH lower than 7, so the solution turning yellow is an indication of an acidic (lower than 7 pH) solution.
Why did the solution eventually turn red?
carbon dioxide reacts with water to produc carbonic acid. As carbonic acid dissociates, the solution becomes more yellow, indicating a lower pH. When light is available and a plant is added, the solution returns to its original red color.