I did this question but I got 4.18 as the pH. I'm confused to how you solve this and get the right answer.
This a question in which NaOH is added to weak acid lets say HA.
First write the balanced equation and since you are mixing volumes so there is a change in molarity so work in mmol to check after the reaction what all is left.
R NaOH + HA ---> Na+ A- + H2O(l)
I 15 25 0
F 0 10 15 -
Finally in the solution you have weak acid and its conjugate base. So its a Buffer and use Henderson Hasselbach equation to calculate the pH.
pH is 4.18
I think the correct answer was marked as 2.62 on the quiz. I put 4.18 and it said it was incorrect.
You can flag the question.