Chemistry

posted by .

Butyric acid (HC4H7O2) is a weak acid with the stench of rancid butter

1.) write the equation for the dissociation of HC4H7O2 in water

2.)the pH of .5 M HC4H7O2 is 2.56 calculate Ka of butyric acid

3.) Write the equation for the hydrolysis of C4H7O2-

4.) Calculate Kb for C4H7O2-

5.) Calculate the pH of a buffer solution in which the concentration of butyri acid= .36 M and the concentration of C4H7O2- is .31 M.

  • Chemistry -

    1.
    HC4H7O2 + H2O ==> H3O^+ + C4H7O2^-

    2.
    pH = -log(H3O^+)
    -2.56 = log(H3O^+)
    (H3O^+) = about 2.8E-3 but you need to do it more accurately. Let HB stand for butyric acid, then
    .......HB + H2O ==> H3O^+ B^-
    I.....0.5M...........0.....0
    C......-x...........x.......x
    E.....0.5-x.........x.......x

    Ka = (H3O^+)(B^-)/(HB)
    You know (H3O^+) = about 2.8E-3, that's also B^-. Substitute into Ka expression and solve for Ka.

    3.
    C4H7O2^- + H2O ==> H3O^+ + HC4H7O2

    4.
    Kb for B^- = (Kw/Ka for HB)

    5. Use the Henderson-Hasselbalch equation.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Chemistry

    Add 0.010 mol of solid sodium butanate, NaC4H7O2 to 100.0 mL of 1.0 M butanoic acid. No volume change. Ka for HC4H7O2=1x10^5. I get pH 6. Rught?
  2. chemistry

    propanoic acid ch3ch2cooh is a weak acid which has a value for dissociation content of ka = 6.3 x 10^-6 calculate the pH of an aqueous solution of propanoic acid containing 37 g of propanoic acid per litre. i'm stumbled on this one.. …
  3. Chemistry

    The foul odor of rancid butter is due largely to butyric acid, a compound containing carbon, hydrogen, and oxygen. Combustion analysis of a 4.30-g sample of butyric acid produced 8.59g CO_2 and 3.52 g H_2O.Find the empirical formula …
  4. Chemistry

    The pH of a weak monoprotic acid, HA, is 4.55. It took 39.22 ml of 0.2334 M NaOH to titrate 25.00 ml of the acid. a. Write an equation for the above reaction. b. Calculate the molarity of the weak acid c. Write the equilibrium equation. …
  5. Chemistry

    In the titration of a weak acid with a strong base, the pH at the equivalence point is affected mostly by a.hydrolysis (reaction with water) of the weak acid b.the dissociation of water molecules c.the presence of excess base d.the …
  6. chemistry

    what volume of butyric acid would be needed to make 25.0mL of a 1.0M solution?
  7. chemistry

    what volume of butyric acid would be needed to make 25.0mL of a 1.0M solution?
  8. chemistry

    2- A 0.310 M solution of a weak acid, HX, has a pH of 2.53 a. Find the [H+] and the percent ionization of nitrous acid in this solution. b. Write the equilibrium expression and calculate the value of Ka for the weak acid. c. Calculate …
  9. Chemistry

    Need help with AP chemistry, specifically Acids and Bases The acid ionization constant, Ka, for propanoic acid, C2H5COOH, is 1.3  10 -5 . (a) Write the expression for the acid-dissociation constant, Ka for propanoic acid. (b) …
  10. chemistry

    i need help solving this Benzoic acid is a weak, monoprotic acid (Ka = 6.3 × 10−5). Calculate the pH and the percent dissociation of each of the following solutions of benzoic acid. Then use Le Châtelier’s principle to explain …

More Similar Questions