pH-Titrationskurve

Aufzeichnung einer vollständigen Säure-Base-Titrationskurve mit pH-Meter

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

Ziel

pH-Messungen während einer Säure-Base-Titration aufzeichnen und eine vollständige S-förmige Titrationskurve mit Äquivalenzpunkt und Pufferbereichen erstellen.

Hintergrund

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.

Sicherheitswarnungen

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

Erforderliche PSA

goggles gloves lab_coat

Materialien

  • 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)

Ausrüstung

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

Durchführung

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.

Erwartete Ergebnisse

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.

Aufräumen

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

Details

Kategorie
Titrations
Schwierigkeit
Intermediate (High School)
Dauer
50 Min.
Geschätzte Kosten
$15,00
Schritte
6
Materialien
4

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Frequently Asked Questions

What is the objective of pH-Titrationskurve?
pH-Messungen während einer Säure-Base-Titration aufzeichnen und eine vollständige S-förmige Titrationskurve mit Äquivalenzpunkt und Pufferbereichen erstellen.
How difficult is pH-Titrationskurve?
This experiment is rated as Intermediate (High School). It takes approximately 50 minutes to complete.
What safety precautions are needed for pH-Titrationskurve?
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 pH-Titrationskurve?
The main materials required are: Hydrochloric acid (HCl), Sodium hydroxide (NaOH), pH buffer solutions, Distilled water.
What results should I expect from pH-Titrationskurve?
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.