Copper Sulfate (CuSO₄)

Preparation

• Copper sulfate can be prepared by:

  • Reacting copper metal with hot concentrated sulfuric acid:

Cu + 2H2SO4 → CuSO4 + SO2 + 2H2O

• Reacting copper oxide with dilute sulfuric acid:

CuO + H2SO4 → CuSO4 + H2O

Properties

• Physical Appearance: Blue crystalline solid when hydrated (CuSO₄·5H₂O) and a white powder when anhydrous (CuSO₄).

• Solubility: Soluble in water, with a slightly acidic taste.

• Nature: Ionic compound.

• Melting Point: 110°C (230°F) for the pentahydrate form.

• Chemical Nature: Strong oxidizing agent, reactive with many reducing agents.

Uses

1. Fungicide and Algaecide: Used to control plant diseases and algae growth in water bodies.

2. Textile and Leather Industry: Used in dyeing and tanning processes.

3. Electroplating: Utilized in electroplating and as a catalyst in various chemical reactions.

4. Medical Use: Historically used as an emetic, but not recommended anymore due to high toxicity.

Storage

• Store in a cool, dry place, away from heat and direct sunlight.

• Keep in a tightly closed container to minimize exposure to air and moisture.

• Store away from strong reducing agents, acids, and flammable materials to prevent chemical reactions.

Assay

• Method: Complexometric titration using ethylenediaminetetraacetic acid (EDTA).

Procedure:

1. Prepare a standard EDTA solution of known concentration.

2. Weigh a sample of copper sulfate and dissolve in distilled water.

3. Add ammonium buffer to adjust the pH to around 9-10.

4. Add a few drops of murexide indicator.

5. Titrate with the standardized EDTA solution until the color changes from wine-red to blue-violet.

6. Calculate the concentration of copper sulfate using the volume of EDTA used.