CO_2 gas will react with water to form carbonic acid (H_2 CO_3) in solution. If aquatic plants in this solution consume CO_2 while performing photosynthesis, what happens to the solution\'s pH? What natural molecule is the terminal electron acceptor within the light dependent stage of oxygenic photosynthesis? Describe the process of how you observed the Hill reaction take place in the photosynthesis lab: (What molecules/substances and equipment did you use?) If you plotted table 6.4 from the photosynthesis lab protocol on a graph to display solution absorbance as a function of time, identify the dependent and independent variables: The use of the pH indicator BTB allows you to qualitatively observe the change in a solution\'s pH. If an aquatic plant sample was placed into a blue solution of BTB and placed in the dark, what process is occurring if the solution changes to yellow? Solution (1) Carbon dioxide will lower the pH of water forming H2CO3. When plants absorb carbon dioxide from the water, the pH will rise. (2) In light dependent stage of Photosynthesis the final electron acceptor is NADP..