An unknown colorless solution turns red when paramethyl red is added. It turns orange when erythrosine is added. Choose another indicator that will give a more precise value for the pH of the solution
a. Metacresol Purpleb. Thymolphthalein
c. Quinaldine Red
d. Ethyl Red

• A. a & c
• B. b & c
• C. c & d
• D. b & d

Answer: (A)