CHEMISTRY

posted by .

A buffer that is 0.271 M in acid, HA, and 0.150 M in the potassium salt of its conjugate base, KA, has a pH of 2.85. What is the pH of the buffer after 130. mL of 0.155 M LiOH is added to 0.650 L of this buffer? Assume that the volumes are additive.

  • CHEMISTRY -

    First determine pKa.
    pH = pKa + log(A^-)/(HA)
    I have approximately 3 but you need to be more accurate than that.
    650 mL x 0.271M = about 170 mmoles
    650 mL x 0.150M = about 95 mmoles

    mmoles LiOH added = 130 x 0.155M = about 20 mmoles.
    ...........HA + OH^- ==> A^- + H2O
    initial...170....0........95
    added...........20
    change...-20....-20......+20
    equil....150.....0........115
    Substitute the equil values (after refining them) into the HH equation and solve for pH.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. CHEMISTRY

    HOW CAN U TELL IF HNO3 +KNO3 IS A BUFFER SOLUTION A buffer solution must contain a weak acid and its conjugate base OR a weak base and its conjugate acid. HNO3 is a strong base and KNO3 is the salt of a strong base (KOH) and a strong …
  2. Chemistry

    A buffer is prepared by mixing 110. mL of 0.442 M HCl and 0.545 L of 0.400 M sodium acetate. How many grams of KOH must be added to 0.500 L of the buffer to change the pH by 0.10 units?
  3. Chemistry

    Two of the questions my teacher put on the review sheet for our Acid/Base test are 1) what is the characteristic property of a buffer solution?
  4. CHEMISTRY

    A buffer that is 0.271 M in acid, HA, and 0.150 M in the potassium salt of its conjugate base, KA, has a pH of 2.85. What is the pH of the buffer after 130. mL of 0.155 M LiOH is added to 0.650 L of this buffer?
  5. Chemistry

    How could you prepare a buffer if only acetic acid, HCl and NaOH are available?
  6. chemistry

    Write an equilibrium reaction for a buffer system made of the weak base, B, and its conjugate acid. If the buffer contains 1.05 M of B and 0.750M conjugate acid and has a pH of 9.50, what is the pH after 0.0050 mol HCl is added to …
  7. Chemistry

    Select the statements that correctly describe buffers.?
  8. Chemistry

    Buffer capacity is a measure of a buffer solution\'s resistance to changes in pH as strong acid or base is added. Suppose that you have 165 mL of a buffer that is 0.360 M in both benzoic acid (C6H5COOH) and its conjugate base (C6H5COO–). …
  9. Chemistry

    Buffer capacity is a measure of a buffer solution\'s resistance to changes in pH as strong acid or base is added. Suppose that you have 165 mL of a buffer that is 0.360 M in both benzoic acid (C6H5COOH) and its conjugate base (C6H5COO–). …
  10. Chemistry

    The pH of a buffer can be predicted using the Hendersen-Hasselbach equation: pH=pKa+ log([conjugate base][conjugate acid]) The choice of the conjugate acid-base pair (as you did in the previous questions) determines the pKa value to …

More Similar Questions