Chemistry

posted by .

HF + NaOH =NaF + H2O
What will be the pH of a solution produced when 40 mL of 0.25 M HF is titrated with 80 mL of 0.125M NaOH? Ka for HF is 3.5*10^-4

  • Chemistry -

    40 mL x 0.25M = 10.0 millimols HF.
    80 mL x 0.125M = 10.0 mmols NaOH
    So you are at the equivalence point and the pH will be determined by the hydrolysis of the NaF.
    (NaF) = 10 mmols/120 mL - 0.0833M

    ..........F^- + HOH ==> HF + OH^-
    init..0.0833............0.....0
    change...-x.............x.....x
    equil.0.0833-x...........x....x

    Kb for F^- = (Kw/Ka for HF) = (HF)(OH^-)/(F^-)
    Substitute the equil line from the ICE chart into the K expression and solve for x = (OH^-) then convert to pH.

  • oops--Chemistry -

    See line 5.
    (NaF) = 10 mmols/120 mL - 0.0833M
    Replace the - with =

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. chemistry

    Can you help me with the following: Calculate the pH that results when 25 mL of .1M HCL is titrated with .1M NaOH solution run in from a buret at each of the stages of volume of .1 M NaOH add in 5.0 mL incrememnts beginning with 0 …
  2. Chemistry

    The Question Is: "A student weighs 0.347 g of KHP on a laboratory balance. The KHP was titrated with NaOH and the concentration of the NaOH determined to be 0.110 M. For the second titration, the student correctly diluted 6 M HCl from …
  3. College Chemistry

    "A student weighs 0.347 g of KHP on a laboratory balance. The KHP was titrated with NaOH and the concentration of the NaOH determined to be 0.110 M. For the second titration, the student correctly diluted 6 M HCl from the reagent shelf …
  4. College Chemistry

    1) A 25mL sample of the .265M HCI solution from the previous question is titrated with a solution of NaOH. 28.25mL of the NaOH solution is required to titrate the HCl. Calculate the molarity of the NaOH solution. 2) A 1.12g sample …
  5. Chemistry

    A 25.0mL sample of a 0.100M solution of acetic acid is titrated with a 0.125M solution of NaOH. Calculate the pH of the titration mixture after 10.0, 20.0, and 30.0 mL of base have been added.
  6. Chemistry

    a 15.00mL sample of NaOH was titrated to the stoichiometric point with 17.40mL of 0.2340M HCl. a) what is the molar concentration of the NaOH solution?
  7. chemistry

    If it requires 30.0 milliliters of 1.2 molar HCl to neutralize 20.0 milliliters of NaOH, what is the concentration of the NaOH solution?
  8. chemistry

    A volume of 100mL of 1.00 M HCl solution is titrated with 1.00 M NaOH solution. You added the following quantities of 1.00 M NaOH to the reaction flask. Classify the following conditions based on whether they are before the equivalence …
  9. Chemistry

    In this experiment NaOH is standardized to titrate it with vinegar so thtat the percent by mass of the acetic acid can be determined. How does dissolved CO2 in distilled water affect the accuracy of the determination of a NaOH solution's …
  10. Chemistry

    An impure sample of (COOH)2 · 2 H2O that has a mass of 2.9 g was dissolved in water and titrated with standard NaOH solution. The titration required 32.4 mL of 0.144 mo- lar NaOH solution. Calculate the percent (COOH)2 · 2 H2O in …

More Similar Questions