Question

Bromothymol blue is an indicator that can be used to determine the effects photosynthesis and cellular respiration. As more CO2 is added, it turns yellow. When more O2 is added, it turns blue.

A plant is placed in water while a student blows bubbles into the water with bromothymol blue. The water turns yellow. After 15 minutes, the water returns to a blue-ish color.

How more O2 added, causing the water turn back to blue?

Answer 1

Bromothymol blue is an indicator for weak acids and bases.It is used to observe photosynthetic acvtivities and for respiratory indication.

Blue Bromothymol indicator will turn to green then to yellow when CO2 is added.When O2 is added, no effect is noticed in the Blue Bromothymol because Oxygen doesnot affect the pH.

In a summary, the color indication follows;

• Yellow-to indicate acidic
• Green-for neutral solutions
• Blue-for alkaline solutions.