Zadanie 1a
Hydrochloric acid, HCl(aq), and hydroiodic acid, HI(aq), ionize completely in water, whereas propanoic acid, CH3CH2COOH(aq), ionizes only partly. 25.0 cm3 of 0.200 mol dm−3 HCl(aq) was titrated with sodium…
Weak acid and base calculations with Ka and Kb
Derive Ka × Kb = Kw for a conjugate pair, calculate the pH of a weak acid or weak base solution from its Ka or Kb (or Ka from pH) using the usual approximations, and convert between Ka, pKa, Kb and pKb.
Tę umiejętność sprawdza 10 zadań wzorowanych na arkuszach IB z lat 2023–2026.
Zadania sprawdzające tę umiejętność: 10 Otwórz w wyszukiwarce z filtrami
Zadanie 34
The table gives data for four bases at 298 K. Which base has the weakest conjugate acid? A. N2H4 B. C2H5NH2 C. C6H5NH2 D. C5H5N
- Tabela do uzupełnienia
Zadanie 26
At 298 K the pKa of methanoic acid is 3.75 and the pKa of ethanoic acid is 4.76. Which statement is correct for solutions of these acids with the same concentration? A. Ethanoic acid is a stronger acid than methanoic…
Zadanie 29
Which combination is correct for a strong acid and its conjugate base? A. The pKa of the acid is low and the Kb of the conjugate base is low B. The pKa of the acid is low and the Kb of the…
Zadanie 25
Using the data in the table, which conjugate base is the weakest? A. CN− B. CH3COO− C. NO2− D. CHCl2COO−
- Tabela do uzupełnienia
Zadanie 27
A 20.0 cm3 sample of a weak monoprotic acid, HA, was titrated with sodium hydroxide solution of concentration 0.100 mol dm−3. What is the pKb of the conjugate base of HA, A−? A. 3 B. 5 C. 9 D. 11
- Materiał graficzny
Zadanie 1c
A neutralization curve for a weak acid, HA, titrated with a strong base is shown. (i) Estimate the pKa of HA. (ii) Explain, using an equation, why the pH changes very little when small volumes of strong base are added to the weak acid in the buffer…
- Materiał graficzny
Zadanie 5a
The concentration of an ethanoic acid solution was found by titration with a 0.150 mol dm−3 standard solution of potassium hydroxide, KOH(aq), using an indicator to detect the end point. (i) Calculate the pH of the potassium hydroxide solution.…
Zadanie 26
The pKa of the ammonium ion, NH4+, is 9.25 at 298 K. What is the pKb of its conjugate base, NH3, at this temperature? A. −4.75 B. 4.75 C. 9.25 D. 23.25
Zadanie 28
A weak acid has a concentration of 0.10 mol dm−3 and Ka = 1.0 × 10−7. Which value is closest to the pH of the solution? A. 1 B. 4 C. 7 D. 8