science

posted by .

A 0.513 M solution of a weak base has a pH of 11.4. What is the Kb of the base?

  • science -

    2.64*10^-5

  • science -

    We will assume that this is monobasic and the temp is 25C so that Kw=10^-14

    If pH is 11.4 then pOH is 14-11.4 = 2.6

    so [OH-] = 10^-2.6 = 2.512 x 10^-3

    assuming that [weak base] at equilibrium is large compared with [OH-] then

    Kb is approximately [OH-]^2/[weak base]

    Kb=(2.512 x 10^-3)^2/0.513

    =1.23 x 10^-5

    but check my maths.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Chemistry

    If an equal number of moles of the weak acid HOCN and the strong base KOH are added to water, the resulting solution will be acidic, basic or neutral?
  2. Organic Chem

    Potassium tert-butoxide is a common base for E2 reactions because it is _______. A. weak base B. an organic base C. a strong base D. a bulky base
  3. chemistry; acids and bases

    Since Ka x Kb = Kw, is the conjugate base of a weak acid a weak base or a strong base?
  4. science

    the ph of a 0.280m solution of a weak base. B has been measured ph --8.69. using this information. calculate the base ionisationconstant kbof b
  5. Chemistry 12

    name a compound that acts as a weak base?
  6. chemistry

    A 1.0 M acetic acid solution (CH3COOH, pKa = 4.7) is neutralized by dissolving NaOH(s) (a strong base) in the solution. Estimate the pH at the equivalence point of the neutralization process: 4.7 7.0 9.3 Which one of the following …
  7. analytical chemistry

    A solution containing 0.40 M B (a weak base) and 0.20 M BH+ (the salt of the weak base) has a pH = 10.30. What is the pH after 25 mmol of HCl is added to 250 mL of this solution?
  8. AP Chemistry

    A solution is prepared by titrating a 100.0 mL sample of 0.10 M HF (Ka = 7.2 × 10-4) with 0.10 M NaOH a. Does the solution contain a strong acid with a strong base, a strong acid with a weak base, a weak acid with a strong base, or …
  9. AP Chemistry

    A solution is prepared by titrating a 100.0 mL sample of 0.10 M HF (Ka = 7.2 × 10-4) with 0.10 M NaOH a. Does the solution contain a strong acid with a strong base, a strong acid with a weak base, a weak acid with a strong base, or …
  10. SCIENCE PLZZ HELP!!!

    Given equal concentrations, which of the following produces the fewest hydronium ions in an aqueous solution?

More Similar Questions