The titration curve of a weak base like ammonia with a strong acid like hydrochloric acid is the mirror image of the titration curve of a weak acid with a strong base.

Using the ICE table and substituting the Kb value, we calculate the initial pH of 50 mL of 0.1 M ammonia to be 11.11. Addition of 25 mL of 0.1 M hydrochloric acid to this solution of ammonia results in a buffer with an equal concentration of ammonia and ammonium ions. The pH of this buffer can be calculated by substituting these values into the Henderson-Hasselbalch equation, which shows that at this point, also known as the half-equivalence point, the pH is equal to pKa. Continuing the titration to the equivalence point would mean that a total of 50 mL of 0.1 M hydrochloric acid would have been added, converting all the ammonia molecules to ammonium ions. At this point, the ammonium ions undergo hydrolysis to generate hydronium ions, making the solution acidic, and an ICE table calculation shows that the pH is 5.28. After the equivalence point, as the hydronium ions predominate the solution, the pH further drops to 1.6. The titration endpoint is detected using the indicator methyl red, which exhibits a color change in the desired pH range.

Tags
TitrationWeak BaseStrong AcidAmmoniaHydrochloric AcidPH CalculationICE TableHenderson Hasselbalch EquationHalf equivalence PointEquivalence PointAmmonium IonsHydrolysisHydronium IonsMethyl Red Indicator

Dal capitolo 3:

article

Now Playing

3.4 : Titration of a Weak Base with a Strong Acid

Acid–Base Titration

4.0K Visualizzazioni

article

3.1 : Titolazione acido-base: panoramica

Acid–Base Titration

6.2K Visualizzazioni

article

3.2 : Titolazione di un acido forte con una base forte

Acid–Base Titration

4.5K Visualizzazioni

article

3.3 : Titolazione di un acido debole con una base forte

Acid–Base Titration

1.5K Visualizzazioni

article

3.5 : Titolazione di un acido debole con una base debole

Acid–Base Titration

1.9K Visualizzazioni

article

3.6 : Composizione della soluzione durante le titolazioni acido/base

Acid–Base Titration

378 Visualizzazioni

article

3.7 : Miscele di acidi

Acid–Base Titration

400 Visualizzazioni

article

3.8 : Titolazione in solventi non acquosi

Acid–Base Titration

502 Visualizzazioni

article

3.9 : Titolazione di una base poliprotica con un acido forte

Acid–Base Titration

425 Visualizzazioni

article

3.10 : Titolazione di acidi poliprotici con una base forte

Acid–Base Titration

1.5K Visualizzazioni

article

3.11 : Composizione delle soluzioni di acido poliprotico in funzione del pH

Acid–Base Titration

331 Visualizzazioni

article

3.12 : Buffer: Panoramica

Acid–Base Titration

3.4K Visualizzazioni

article

3.13 : Buffer: Capacità buffer

Acid–Base Titration

815 Visualizzazioni

article

3.14 : Effetto di livellamento

Acid–Base Titration

542 Visualizzazioni

JoVE Logo

Riservatezza

Condizioni di utilizzo

Politiche

Ricerca

Didattica

CHI SIAMO

Copyright © 2025 MyJoVE Corporation. Tutti i diritti riservati