Ascientist wants to test how much of a base can be added to a solution before the ph of the solution changes to above a certain point. the starting ph of the solution is 7.0, and the scientist wants to know when the ph of the solution changes to above 8.0.which ph indicator should the scientist use? a. methyl yellow, which changes from yellow to red around a ph of 4.0 b. congo red, which changes from red to violet around a ph of 5.0 c. alizarin yellow r, which changes from yellow to red around a ph of 10.2 d. phenolphthalein, which changes from colorless to purple around a ph of 8.3