Post a New Question

General Chemistry-Acids/Bases

posted by .

I'm stuck on a couple of similar problems involving pH and acids/bases

1) What is the final pH of a 1L solution that is initially .15 M HF and .2 M NaF after 10 mL of .02 M HCl has been added? Ka=7.2x10^-4

Do i just calculate the total mols of H and divide by the volume, then find the pH?

2.) Calculate the volume of .030 M HNO3 that must be added to a 100mL solution of .25 M NaOh to give a pH of 8.5

This question deals with a strong acid/base, so would I do the same procedure as I would do for number 1? Or would I use a different approach?


  • General Chemistry-Acids/Bases -

    The first problem is a buffer problem. HF is a weak acid and NaF is the salt of the weak acid. Use the Henderson-Hasselbalch equation.
    The second problem is a strong acid/strong base problem. There are no ionization constants involved and you can go from molarities to H^+ and pH.
    Post your work if you get stuck.

  • General Chemistry-Acids/Bases -

    Thanks! I figured out how to do the buffer problem. Can I use the Henderson-Hasselbalch equation for the strong acid/base problem with 0 for the pKa?

  • General Chemistry-Acids/Bases -

    No. The H-H equation has no meaning for a strong acid/strong base because neither HNO3 nor NaOH has a Ka or Kb.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

More Related Questions

Post a New Question