Answer:
D. 6.3 x 10-5 mol/L NaOH
Explanation:
Alizarin yellow is an indicator that is yellow when pH < 10.1. In the same way, thymol blue is blue when pH > 9
That means the pH of the solution is between 9 - 10.1
Any acid as HCl could have a pH of these.
The solution of 3.2x10⁻⁴M NaOH has a pH of:
pOH = -log[OH-] = 3.49
pH = 14-pOH = 10.51. The pH of the solution is not 10.5
Now, the solution of 6.3x10⁻⁵M NaOH has a pH:
pOH = -log[OH-] = 4.2
pH = 14-pOH = 9.8
The pH of the solution could be 9.8. Right option is:
<h3>D. 6.3 x 10-5 mol/L NaOH</h3>
