Titrasi Kompleksometrik EDTA untuk Kesadahan Air

Mengukur kandungan kalsium dan magnesium dalam air

Titrations Advanced (University) 45 menit ~$15,00

Tujuan

Tentukan kesadahan total sampel air dengan menitrasi ion Ca2+ dan Mg2+ yang terlarut dengan EDTA menggunakan indikator Eriochrome Black T.

Latar Belakang

EDTA (ethylenediaminetetraacetic acid) forms stable 1:1 complexes with metal ions. In the presence of Eriochrome Black T indicator at pH 10, the solution is wine-red when metal ions are present and turns blue when all metal ions are complexed by EDTA, marking the endpoint.

Peringatan Keselamatan

  • Ammonia buffer has a strong odor — use in a ventilated area
  • Wear safety goggles
  • EDTA is generally safe but avoid ingestion

APD yang Diperlukan

goggles lab_coat

Bahan

  • Water sample (250 mL)
    Tap water or well water
  • EDTA solution (100 mL)
    0.01M, disodium salt
  • Eriochrome Black T indicator (5 mL)
    Solid or solution
  • Ammonia buffer (pH 10) (20 mL)
    NH₃/NH₄Cl buffer
  • Distilled water (200 mL)

Peralatan

50 mL burette Burette stand and clamp 250 mL Erlenmeyer flask 25 mL pipette White tile

Prosedur

1

Pipette exactly 25.0 mL of the water sample into the Erlenmeyer flask.

2 menit
2

Add 2 mL of ammonia buffer (pH 10) to the flask.

1 menit Ammonia odor — work in ventilated area
3

Add a small amount of Eriochrome Black T indicator. The solution should turn wine-red.

1 menit
4

Fill the burette with 0.01M EDTA solution. Record the initial volume.

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5

Titrate by adding EDTA slowly while swirling. The wine-red color will gradually shift.

10 menit
6

Near the endpoint, add EDTA drop by drop until the color changes sharply from wine-red to blue.

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7

Record the final volume. Repeat for concordant results.

12 menit
8

Calculate total hardness in mg/L CaCO₃ equivalent using the formula: Hardness = (V(EDTA) x C(EDTA) x 100.09 x 1000) / V(sample).

5 menit

Hasil yang Diharapkan

Typical tap water has 100-250 mg/L total hardness (CaCO₃ equivalent). The color change should be a clear transition from wine-red to blue. Soft water requires less EDTA; hard water requires more.

Pembersihan

Dispose of EDTA solutions down the drain (biodegradable at these concentrations). Rinse all glassware.

Detail

Kategori
Titrations
Tingkat Kesulitan
Advanced (University)
Durasi
45 menit
Perkiraan Biaya
$15,00
Langkah
8
Bahan
5

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Frequently Asked Questions

What is the objective of Titrasi Kompleksometrik EDTA untuk Kesadahan Air?
Tentukan kesadahan total sampel air dengan menitrasi ion Ca2+ dan Mg2+ yang terlarut dengan EDTA menggunakan indikator Eriochrome Black T.
How difficult is Titrasi Kompleksometrik EDTA untuk Kesadahan Air?
This experiment is rated as Advanced (University). It takes approximately 45 minutes to complete.
What safety precautions are needed for Titrasi Kompleksometrik EDTA untuk Kesadahan Air?
Key safety precautions include: Ammonia buffer has a strong odor — use in a ventilated area; Wear safety goggles; EDTA is generally safe but avoid ingestion.
What materials are needed for Titrasi Kompleksometrik EDTA untuk Kesadahan Air?
The main materials required are: Water sample, EDTA solution, Eriochrome Black T indicator, Ammonia buffer (pH 10), Distilled water.
What results should I expect from Titrasi Kompleksometrik EDTA untuk Kesadahan Air?
Typical tap water has 100-250 mg/L total hardness (CaCO₃ equivalent). The color change should be a clear transition from wine-red to blue. Soft water requires less EDTA; hard water requires more.