Curva de Titulación de pH

Trazado de una curva completa de titulación ácido-base con pHmetro

Titrations Intermediate (High School) 50 min ~$15,00

Objetivo

Registrar mediciones de pH durante una titulación ácido-base y construir una curva de titulación en forma de S que muestre el punto de equivalencia y las regiones tampón.

Antecedentes

A pH titration curve provides far more information than an indicator-based titration. The S-shaped curve reveals the buffer region, half-equivalence point (where pH equals pKa for weak acids), and the sharpness of the equivalence point. This experiment compares the curves of strong and weak acids.

Advertencias de seguridad

  • HCl and NaOH are corrosive
  • Wear safety goggles and gloves
  • Handle the pH electrode carefully — it is fragile

EPP requerido

goggles gloves lab_coat

Materiales

  • Hydrochloric acid (HCl) (50 mL)
    0.1M
  • Sodium hydroxide (NaOH) (100 mL)
    0.1M
  • pH buffer solutions (3 bottles)
    pH 4, 7, 10 for calibration
  • Distilled water (200 mL)

Equipamiento

50 mL burette Burette stand and clamp 250 mL beaker pH meter with electrode Magnetic stirrer 25 mL pipette Graph paper

Procedimiento

1

Calibrate the pH meter using the three buffer solutions (pH 4, 7, 10).

5 min Handle pH electrode gently
2

Pipette 25.0 mL of 0.1M HCl into the beaker. Record the initial pH.

3 min
3

Fill the burette with 0.1M NaOH. Record the initial volume.

3 min
4

Add NaOH in 1.0 mL increments, recording the pH after each addition. When pH changes rapidly, switch to 0.2 mL increments.

25 min
5

Continue adding NaOH until the pH is above 12. Add a few more points past the equivalence point.

5 min
6

Plot pH (y-axis) versus volume of NaOH (x-axis) to construct the titration curve.

7 min

Resultados esperados

The curve should show a characteristic S-shape: slowly rising pH initially, a steep jump around the equivalence point (pH 7 for strong acid-strong base), then leveling off at high pH. The equivalence point volume should be approximately 25 mL.

Limpieza

Rinse the pH electrode and store in storage solution. Neutralize waste before disposal. Rinse all glassware.

Detalles

Categoría
Titrations
Dificultad
Intermediate (High School)
Duración
50 min
Costo estimado
$15,00
Pasos
6
Materiales
4

Más experimentos

Retrotitulación de Tabletas Antiácidas 60 min Titulación Ácido-Base con Fenolftaleína 45 min Titulación Ácido-Base con Naranja de Metilo 40 min Titulación Complejométrica con EDTA para Dureza del Agua 45 min Titulación con Doble Indicador de Mezcla Carbonato-Bicarbonato 55 min Titulación Conductométrica 50 min Titulación de Vitamina C con Yodo 40 min Titulación por Precipitación (Método de Mohr) 45 min Titulación Redox con Permanganato de Potasio 50 min Titulación Yodométrica de Lejía 50 min

Frequently Asked Questions

What is the objective of Curva de Titulación de pH?
Registrar mediciones de pH durante una titulación ácido-base y construir una curva de titulación en forma de S que muestre el punto de equivalencia y las regiones tampón.
How difficult is Curva de Titulación de pH?
This experiment is rated as Intermediate (High School). It takes approximately 50 minutes to complete.
What safety precautions are needed for Curva de Titulación de pH?
Key safety precautions include: HCl and NaOH are corrosive; Wear safety goggles and gloves; Handle the pH electrode carefully — it is fragile.
What materials are needed for Curva de Titulación de pH?
The main materials required are: Hydrochloric acid (HCl), Sodium hydroxide (NaOH), pH buffer solutions, Distilled water.
What results should I expect from Curva de Titulación de pH?
The curve should show a characteristic S-shape: slowly rising pH initially, a steep jump around the equivalence point (pH 7 for strong acid-strong base), then leveling off at high pH. The equivalence point volume should be approximately 25 mL.