What makes the solution turn clear?

In a lab that my teacher conducted, he had two student blow into a beaker filled with a pink solution using a straw. One solution turned clear and one solution stayed pink. He then told us that the one that remained pink had a greater amount of sodium hydroxide and phenolphthalein. What makes the color turn to clear?What makes the solution turn clear?
Phenolphthalein is an indicator that is pink in a basic solution, but is colourless when the pH of a solution is less than 8. The sodium hydroxide in the solutions made them basic, hence the pink colour.





Your teacher exhaled carbon dioxide gas into the solutions, which reacted with water in them to create carbonic acid. The acid neutralised some of the sodium hydroxide, reducing the pH, making them less basic. The solution that turned colourless had less sodium hydroxide in it, and when the carbonic acid neutralised it, the pH was less than 8, and the solution turned colourless.What makes the solution turn clear?
Phenolphtalein is an indicator that turns pink when the solution is basic, and becomes clear when the solution is acidic. Sodium hydroxide is the base that makes the solutions initially pink. When they blew into the solution, carbon dioxide that they exhaled reacted with water to form carbonic acid:


CO2 + H20 ---%26gt; H2CO3


(basically, acid rain in a beaker). The acid neutralizes the base, turning the solution more and more acidic. When enough of the base is neutralized, the solution turns clear.