Question

A scientist wants to test how much of an acid can be added to a solution before the pH of the solution changes to below a certain point. The starting pH of the solution is 6.0, and the scientist wants to know when the pH of the solution changes to below 5.0.

Which pH indicator should the scientist use?

A.Phenolphthalein, which changes from colorless to purple around a pH of 8.3
B.Cresol red, which changes from yellow to purple around a pH of 7.2
C.Congo red, which changes from red to violet around a pH of 5.0
D.thymolphthalein, which changes from colorless to blue around a pH

Answer 1

@misssunshinexxoxo

Answer 2

Which do you believe it is?

Answer 3

c

Answer 4

???

Answer 5

I believe that is correct; double checking

Answer 6

k

Answer 7

Congo red is the sodium salt of 3,3'-bis. It is a secondary diazo dye. Congo red is water soluble, yielding a red colloidal solution; its solubility is better in organic solvents such as ethanol.

Answer 8

so c

Answer 9

Not sure but think so yes

Answer 10

makes sense

Answer 11

the clue is in the option
congo red changes to to violet at 5 pH so that is your indicator at that pH level