If you blow into a test tube of bromothymol, what happens?
If you blow into a test tube containing bromothymol, a chemical reaction occurs, resulting in a change in color. Bromothymol is a pH indicator, which means it can detect the acidity or basicity of a solution by changing color.
Here's how you can understand and explain the reaction that takes place:
1. Understand bromothymol: Bromothymol is a dye that is usually yellow in its neutral form. When it is dissolved in water, it acts as an indicator, meaning it can show whether a solution is acidic, basic, or neutral based on the color change it undergoes.
2. Know the reaction: When you blow into the test tube, you introduce carbon dioxide (CO2) from your breath into the bromothymol solution. Carbon dioxide reacts with water to form carbonic acid (H2CO3), which is a weak acid.
CO2 + H2O → H2CO3
3. Observe the color change: Carbonic acid is slightly acidic, so it lowers the pH of the solution. In the presence of acids, bromothymol changes its color from yellow to green. Therefore, when carbon dioxide dissolves in the bromothymol solution, the solution turns green.
So, when you blow into a test tube of bromothymol, it changes color from yellow to green due to the formation of carbonic acid (H2CO3) from carbon dioxide (CO2) in your breath.