Konduktometrische Titration

Verfolgung einer Titration anhand der elektrischen Leitfähigkeit

Titrations Advanced (University) 50 Min. ~$20,00

Ziel

Eine Säure-Base-Titration mithilfe von Leitfähigkeitsmessungen statt eines Indikators durchführen und den Äquivalenzpunkt aus dem Leitfähigkeits-Volumen-Diagramm ermitteln.

Hintergrund

In a conductometric titration, electrical conductivity of the solution is measured as the titrant is added. Since different ions have different molar conductivities (H+ and OH- are exceptionally mobile), the conductivity changes non-linearly during titration. The endpoint is found where two straight-line segments of the conductivity curve intersect.

Sicherheitswarnungen

  • HCl and NaOH are corrosive
  • Wear safety goggles and gloves
  • Keep the conductivity probe away from the magnetic stirrer bar

Erforderliche PSA

goggles gloves lab_coat

Materialien

  • Hydrochloric acid (HCl) (100 mL)
    0.1M
  • Sodium hydroxide (NaOH) (100 mL)
    0.1M
  • Distilled water (200 mL)

Ausrüstung

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

Durchführung

1

Pipette 25.0 mL of 0.1M HCl into the beaker. Add 50 mL of distilled water to increase volume for the probe.

3 Min. Handle HCl carefully
2

Place the beaker on the magnetic stirrer. Insert the conductivity probe and the stir bar.

2 Min.
3

Record the initial conductivity reading. Fill the burette with 0.1M NaOH.

3 Min.
4

Add 1.0 mL of NaOH from the burette. Stir for 30 seconds, then record the conductivity and cumulative volume.

2 Min.
5

Repeat step 4, adding 1.0 mL increments, recording conductivity after each addition. Continue until well past the expected endpoint.

25 Min.
6

Plot conductivity (y-axis) versus volume of NaOH added (x-axis). Identify the two linear regions.

8 Min.
7

Draw best-fit lines for the two regions and find their intersection. This is the endpoint.

5 Min.

Erwartete Ergebnisse

Conductivity initially decreases as highly mobile H+ ions are replaced by less mobile Na+ ions. After the endpoint, conductivity increases as excess OH- ions accumulate. The V-shaped graph clearly shows the equivalence point.

Aufräumen

Remove and rinse the conductivity probe carefully. Neutralize waste solutions before disposal. Rinse all glassware.

Details

Kategorie
Titrations
Schwierigkeit
Advanced (University)
Dauer
50 Min.
Geschätzte Kosten
$20,00
Schritte
7
Materialien
3

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Frequently Asked Questions

What is the objective of Konduktometrische Titration?
Eine Säure-Base-Titration mithilfe von Leitfähigkeitsmessungen statt eines Indikators durchführen und den Äquivalenzpunkt aus dem Leitfähigkeits-Volumen-Diagramm ermitteln.
How difficult is Konduktometrische Titration?
This experiment is rated as Advanced (University). It takes approximately 50 minutes to complete.
What safety precautions are needed for Konduktometrische Titration?
Key safety precautions include: HCl and NaOH are corrosive; Wear safety goggles and gloves; Keep the conductivity probe away from the magnetic stirrer bar.
What materials are needed for Konduktometrische Titration?
The main materials required are: Hydrochloric acid (HCl), Sodium hydroxide (NaOH), Distilled water.
What results should I expect from Konduktometrische Titration?
Conductivity initially decreases as highly mobile H+ ions are replaced by less mobile Na+ ions. After the endpoint, conductivity increases as excess OH- ions accumulate. The V-shaped graph clearly shows the equivalence point.