NY Regents Chemistry Exam June 2022
48 An indicator is added to an aqueous solution with a pH value of 5.6. Which indicator is paired with its observed color in this solution? (1) Methyl orange is yellow.
(2) Phenolphthalein is pink.
(3) Bromcresol green is yellow.
(4) Thymol blue is blue.
Explanation: Table M on the Reference Table shows a list of indicators and the pH range at which their colors change. Let's take a look at each indicator at the pH value indicated: 5.6
Methyl orange has a pH range of 3.1–4.4 and color change of red to yellow. This means that if the solution's pH is lower than 3.1, the color will be red and above 4.4 the color will be yellow. Since the pH is 5.6 which is above 4.4, yellow color should be expected.
Answer: 1