QUESTION: A solution is created by measuring 3.60 x 10-3 moles of NaOH and 5.95 x 10-4 moles of
HCl into a container and then water is added until the final volume is 1.00 L. What is
the pH of this solution?

What value would I use for the total moles of the solution? Because I don't think adding them makes sense. I know that from the moles, I can calculate the molarity of NaOH, then pOH and pH (14=pOH+pH), right?

Do a neutralisation, how many moles from which substance will remain.
This calculated for 1 l gives  the remaining concentration. Calculate the pH.

Quote from: ann on March 06, 2023, 10:06:39 PM

What value would I use for the total moles of the solution? Because I don't think adding them makes sense. I know that from the moles, I can calculate the molarity of NaOH, then pOH and pH (14=pOH+pH), right?

As we discussed in the class, when you mix acid and bases a reaction takes place. You need to check how many moles of NaOH or H Cl is left after the reaction. Calculate pH of the solution from the left moles HCl or NaOH / 1L of solution.
                        HCl      +        NaOH ----> NaCl + H₂O
Initial moles  5.95 x 10^-4    3.60 x 10^-3           0     -
Final moles      0                    3.01 *10^{^-3}       5.95 x 10^-4
pH is controlled by left amount of NaOH
Get [OH^-] ,pOH and the pH
Remember NaOH is a strong base.
pH + pOH = 14