posted by .

The triation of 50.00 mL of 0.025 00 M MES with 0.100 0 M NaOH. MES is a weak acid with pKa=6.27. Compute Ve, first. Show what happens at the four stages of the titration: Va = 0,2,5,10,10.1,11,12, and 12.2 mL.


  • Chemistry -

    Can you calculate volume to get to the equivalence point? Do that first.
    a. First stage: at the beginning.
    .........HA ==> H^+ + A^-

    Substitute into the Ka expression and solve for x, then convert to pH.

    b. At the equivalence point you have the salt. The hydrolysis of the salt:
    You will need to determine the concn of the salt. That will be (50*0.025/50+Ve)= ?
    .........A^- + HOH ===> HA + OH^-
    initial.. ?.............0.....0

    Kb for A^- = (Kw/Ka for MES) = (HA)(OH^-)/(A^-)
    Substitute from the ICE chart and solve for x = (OH^-), then convert to pH.

    c. Everything between beginning and the equivalence point.
    mols MES = M x L
    mols NaOH = M x L
    Subtract which will leave an excess of MES PLUS the salt formed. I would use the Henderson-Hasselbalch equation which is pH = pKa + lopg (salt/acid)

    d. Everything after the equivalence point.
    mols EXCESS NaOH/total volume. This will be OH^-, convert to pOH, then to pH.
    Post your work if you get stuck.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. chemistry - titration

    Show that for the titration of a weak acid, HA, with NaOH solution, at half-titer, pH = pKa. Please explain your answer. Thank you. HA + NaOH ==> NaA + HOH Ka for HA = (H^+)(A^-)/(HA) and solve for H^+. (H^+) = Ka*[(HA)/(A^-) When …
  2. Chemistry

    You are carrying out the titration of 100.0 mL of 1.000M acetic acid with 1.000 M sodium hydroxide. Ka = 1.76x10^-5 of acetic acid. (a) Calculate the initial pH of your acetic acid sample. (b) Calculate the pH of the solution after …
  3. Chemistry

    Part A: Unknown Acid use 1gram and mix with 120 mL of distilled water Determine the concentration of the acid by titrating with 0.0998 M of NaOH Concentration of NaOH= 0.0998M Volume of NaOH= 3.5 mL # moles of NaOH= Initial Concentration …
  4. Chemistry

    Consider a weak acid-strong base titration in which 25.0 mL of 0.100 M acetic acid is titrated with 0.100 M NaOH. a) Calculate the pH after the addition of 3.00mL of NaOH. b) What is the pH of the solution before the addition of NaOH …
  5. Chemistry (Titration Curves)

    Which of the following Acid+Base titration combinations would have a buffering region in their plot?
  6. Analytical Chemistry 2

    Consider the titration of the weak acid HA with NaOH. At what fraction of Ve does pH = pKa - 1?
  7. Chemistry help!!

    Consider the titration of the weak acid HA with NaOH. At what fraction of Ve does pH = pKa - 1?
  8. Biochemistry

    1. MES (2-(N-Morpholino)ethanesulfonic acid) is a common buffer used in biochemistry labs to stabilize proteins. The pKa for MES is 6.09. a. What is the pH of 1 liter of a 200 mM MES aqueous solution?
  9. College Chemistry

    I need help with this question!! a sample of pure KHP weighing .8097g dissolved in water and titrated with 40.25 mL of NaOH solution. The same NaOH solution was used to titrate a solution of a weak diprotic acid H2X. A sample of 0.18694g …
  10. chemistry

    You discovered a new diprotic acid, which you have named edmontonic acid. You want to characterize the pKa’s of edmontonic acid, so you perform a titration experiment. Your data are summarized in the table below. Your titration sample …

More Similar Questions