Question

Why does Bromothylmol Blue solution turn yellow when carbon dioxide is added? what reation is occuring to turn it yellow?

Answer 1

Bromothylmol blue solution is commonly used in acid-base titration reactions. It becomes yellow when the pH is lower than 6.0. This is the reaction that occurs at equivalence point CO₂ + H₂o ↔ H₂CO₃. Carbon dioxide turns the color from blue into yellow.