Chemistry

posted by .

A 20.2 mL sample of a weak monoprotic acid, HX, requires 50.0 mL of 0.060 M NaOH to reach the equivalence point. After the addition of 30.0 mL of NaOH, the pH is 5.50. What is the Ka of HX?

  • Chemistry -

    millimols HX initially = 50 x 0.06 = 3.00
    mmols NaOH added for pH 5.50 = 30.0 x 0.06 = 1.8

    ............HX + NaOH ==> NaX + H2O
    initial....3.00....0.......0......0
    add...............1.8...............
    change.....-1.8..-1.8.......+1.8...+1.8
    equil.......1.2.....0......1.8......1.8

    Plug 5.50 for pH and the other info into the Henderson-Hasselbalch equation. Solve for pKa and convert top Ka.

  • Chemistry -

    6.5

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Chemistry

    In this case, the inflection point, and equivalence, occurs after 23.25mL of 0.40 M NaOH has been delivered. Moles of base at the equivalence point can be determined from the volume of base delivered to reach the equivalence point …
  2. chemistry

    A 20.1 mL sample of a weak monoprotic acid, HX, requires 50.0 mL of 0.060 M NaOH to reach the equivalence point. After the addition of 30.0 mL of NaOH, the pH is 4.90. What is the Ka of HX?
  3. Chemistry

    A 22.3 mL sample of a weak monoprotic acid, HX, requires 50.0 mL of 0.040 M NaOH to reach the equivalence point. After the addition of 30.0 mL of NaOH, the pH is 5.30. What is the Ka of HX?
  4. Chemistry

    A 22.3 mL sample of a weak monoprotic acid, HX, requires 50.0 mL of 0.040 M NaOH to reach the equivalence point. After the addition of 30.0 mL of NaOH, the pH is 5.30. What is the Ka of HX?
  5. Chemistry

    A 0.225g sample of a weak monoprotic acid requires 37.50 mL of 0.100 M NaOH solution to reach the equivalence point. What is the molar mass of the acid?
  6. chemisry

    A 0.1 molal solution of a weak monoprotic acid was found to depress the freezing point of water 0.1930C. Determine the Ka of the acid. You can assume 0.1 molal and 0.1 molar are equivalent. 100 ml of a 0.1M solution of the above acid …
  7. chemistry

    a. A 0.1 molal solution of a weak monoprotic acid was found to depress the freezing point of water 0.1930C. Determine the Ka of the acid. You can assume 0.1 molal and 0.1 molar are equivalent. b. 100 ml of a 0.1M solution of the above …
  8. chemistry

    You are titrating an unknown weak acid you hope to identify. Your titrant is a 0.0935 mol/L NaOH solution, and the titration requires 39.9 mL to reach the equivalence point. How many moles of acid were in your sample?
  9. Chemistry

    Titration of 50.0 ml of acetic acid reaches equivalence after delivery of 22.5 ml of standardized NaOH 0.21 M. What is the initial concentration of acetic acid and what is the pH of the solution?
  10. Chemistry

    A 22.6 mL sample of a weak monoprotic acid, HX, requires 50.0 mL of 0.050 M NaOH to reach the equivalence point. After the addition of 30.0 mL of NaOH, the pH is 4.90. What is the Ka of HX?

More Similar Questions