Understanding the Color Changes of Solution A
What is Solution A and how does its color change when specific indicators are added?
Solution A is yellow when alizarin yellow is added and blue when thymol blue is added. Which of the following correctly identifies Solution A?
A. 3.2 x 10-4 mol/L HCI
B. 3.2 x 10-4 mol/L NaOH
C. 6.3 x 10-5 mol/L HCI
D. 6.3 x 105 mol/L NaOH
Answer
Correctly identifies Solution A as D. 6.3 x 10-5 mol/L NaOH
Solution A exhibits color changes dependent on the pH level when specific indicators are added. Alizarin yellow, which is yellow when pH is less than 10.1, turns Solution A yellow. On the other hand, thymol blue, which is blue when pH is greater than 9, causes Solution A to turn blue.
Based on the color changes observed, it can be inferred that the pH of Solution A falls within the range of 9 to 10.1. This indicates that Solution A is basic in nature.
Upon analyzing the given options, it is revealed that the solution containing 6.3 x 10-5 mol/L NaOH aligns with the pH range observed in Solution A. NaOH is a strong base with a pH of 9.8, making it a suitable candidate for the identity of Solution A.
Therefore, the correct identification of Solution A is 6.3 x 10-5 mol/L NaOH.