chemistry

1. 25.0mL of 0.20M Propanic acid (HC3H5O2, Ka = 1.3×10-5) is titrated using 0.10M NaOH. Calculate the following pH. Show your work.

a. When 0.0 mL NaOH is added.







b. When 25.0 mL NaOH is added








c. When 50.0 mL NaOH is added







d. When 75.0mL NaOH is added.

  1. 👍 0
  2. 👎 0
  3. 👁 287
asked by fun
  1. Let's call the acid HP.
    a.
    .......HP ==> H^+ + P^-
    I.....0.2M....0.....0
    C......-x.....x.....x
    E....0.2-x....x.....x

    Plug the E line into the Ka expression and solve for x = (H^+), then convert to pH.

    b is done with the Henderson-Hasselbalch equation.

    c is the equivalence point and the rxn is HP + NaOH ==> NaP + H2O
    The pH is determined by the hydrolysis of the salt NaP. The concentration of the salt is mols NaP/L. mols NaP = M x L = 0.2 x 0.025 = 0.005. L = 50 mL from the beginning + 50 mL added NaOH = 75 mL = 0.075 L so M NaP = 0.005/0.075 - 0.0667. The hydrolysis works this way.
    .........P^- + HOH ==> HP + OH^-
    I.....0.0667...........0.....0
    C......-x..............x.....x
    E....0.0667-x..........x.....x

    Kb for P^- = (Kw/Ka for HP)
    = (x)(x)/(0.0667-x). Solve for x = (OH^-) and convert to pH.

    D. You have excess OH^-. Calculate that and convert to pH.

    Post your work if you have questions and PLEASE tell us exactly what you don't understand.

    1. 👍 0
    2. 👎 0
    posted by DrBob222

Respond to this Question

First Name

Your Response

Similar Questions

  1. chemistry

    calculate the pH of the solution when 25.0ml of 0.0920M HCL is titrated with 0.15ml, 23.0ml, 30.0ml of 0.10M NaOH

    asked by nathalie on January 23, 2013
  2. chemistry

    1. if 15.0mL of 4.5 M NaOH are diluted with water to a volume of 500mL, what is the molarity of the resulting solution? 2. in a acid-base titration, 33.65mL of an 0.148 M HCL solution were required to neutralize 25.00mL of a NaOH

    asked by djella on October 25, 2011
  3. chemistry

    .0900g of unknown acid(diproctic acid) with empirical formular(CHO2) is dissolved in 30.0ml of water and the rest is titrated to the endpoint with 50.0ml of .040 M NaOH(aq) determine the molecular formula of the acid?

    asked by tesh on October 23, 2012
  4. Chemistry

    .12M Lactic Acid (HC3H5O3, Ka=1.4x10^-4) is mixed with .10M NaC3H5O3 to form 1.00L solution. A. Calculate the pH of the solution after the addition of 50.0mL of 1.00M NaOH. B. Calculate the pH of the solution after the addition of

    asked by Emma on March 28, 2010
  5. Chemistry

    If i titrated 25.0mL of 0.500M HCl with 0.500M NaOH and then 25.0mL of 0.500M of an unknown weak acid HA with 0.500M NaOH. How would the two titration curves compare at 10 or 15mL of NaOH Beyond equivelance pts? I think that they

    asked by Jake on March 3, 2011
  6. analytical chemistry

    Calculate the ph during the titration of 20.0ml 0.5000M ethanoic acid Ka=0.0000175 with 0.500M NaOH after the addition of 0.0ml and 10.0ml NaOH

    asked by Anonymous on June 15, 2018
  7. Chemistry

    WOULD THE VOLUME OF A 0.10M NAOH SOLUTION NEEDED TO TITRATE25.0ML OF A 0.10M HNO2 ( A WEAK ACID)SOLUTION BE DIFFERENT FROMTHAT NEEDED TO TITRATE 25.0ML OF A 0.10M HCL (A STRONGACID)SOLUTION?

    asked by Naomie on June 12, 2013
  8. 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

    asked by Jessica on October 25, 2010
  9. Chemistry

    Can someone please help me here? It's review for my test. Thanks! Calculate the expected pH of the buffer prepared in Part I of this lab. The Ka of acetic acid is 1.8 x 10-5 Calculate the expected pH when 10.0mL of 0.10M HCl is

    asked by Matt on April 8, 2014
  10. Chemistry

    Calculate the concentration of a 50.0mL sample of HBr acid, which was titrated with 37.7 mL of 0.57 M NaOH base. Why is an overshot endpoint not a good titration?

    asked by Jared on April 10, 2008

More Similar Questions