Question

A student set up an experiment to show that carbon dioxide is consumed by Elodea plants during photosynthesis. She filled two test tubes with distilled water and placed a piece of Elodea in each of the tubes. She added a drop of phenol red, which turns red in a basic solution and yellow in an acidic solution. She blew in each tube to add carbon dioxide, which caused the distilled water to become more acidic so the phenol red turned yellow. She wrapped Tube A in aluminum foil and left Tube B exposed to the light. After 15 minutes, what should she expect to observe?

Multiple Choice
A.Both tubes will have turned red.
B.Tube A will be yellow and Tube B will be red.
C.Both tubes will remain yellow.
D.Tube A will be red and Tube B will be yellow.

Answer 1

After 15 minutes, Tube A will be yellow and Tube B will be red.

Step-by-step explanation:

After 15 minutes, the student should expect to observe that Tube A wrapped in aluminum foil will turn yellow, while Tube B exposed to the light will remain red. This is because Elodea plants undergo photosynthesis in the presence of light, consuming carbon dioxide and producing oxygen. The phenol red in Tube A will turn yellow due to the consumption of carbon dioxide, while the phenol red in Tube B will remain red indicating the presence of carbon dioxide.