0.1 Normal H2SO4 Preparation
Introduction
Sulfuric acid (H2SO4) is a strong acid commonly used in various laboratory procedures, including titrations, precipitation reactions, and acid-base neutralizations. In this article, we will explain how to prepare a 0.1 normal (N) solution of sulfuric acid, which is a common concentration used in many laboratory applications.
Understanding Normality (N)
Before we dive into the preparation of 0.1 N H2SO4, it's essential to understand the concept of normality (N). Normality is a measure of the concentration of a solution, defined as the number of equivalents of a solute per liter of solution. In the case of sulfuric acid (H2SO4), one equivalent is equal to 49.04 grams (the molecular weight of H2SO4 divided by 2, since it has two acidic hydrogens).
Preparation of 0.1 N H2SO4
To prepare a 0.1 N solution of sulfuric acid, you will need:
Materials:
- Sulfuric acid (H2SO4) (conc. approximately 18 M)
- Distilled water
- Volumetric flask (1 L)
- Pipettes (10 mL and 100 mL)
Procedure:
- Calculate the volume of concentrated sulfuric acid required: To prepare 1 liter of 0.1 N H2SO4, you need to calculate the volume of concentrated sulfuric acid required. Since the normality of the solution is 0.1, you need 0.1 equivalents of H2SO4 per liter of solution. The molecular weight of H2SO4 is 98.08 g/mol, and since it has two acidic hydrogens, one equivalent is equal to 49.04 g.
Moles of H2SO4 required = 0.1 equivalents/L × 49.04 g/equivalent = 4.904 g/L
Concentrated sulfuric acid is approximately 18 M (moles per liter). To find the volume of concentrated acid required, divide the moles of H2SO4 required by the molarity of the concentrated acid:
Volume of concentrated acid required = 4.904 g/L ÷ 18 M = 0.272 mL
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Dilute the concentrated sulfuric acid: Using a pipette, slowly add 0.272 mL of concentrated sulfuric acid to a 1 L volumetric flask. Be careful when handling concentrated sulfuric acid, as it can cause severe burns and damage to skin and eyes.
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Add distilled water: Add distilled water to the volumetric flask, slowly, while gently swirling the flask. Make sure to leave enough space at the top for the acid to mix properly.
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Mix and rinse: Mix the solution thoroughly by inverting and rotating the flask several times. Rinse the pipette and the neck of the flask with a small amount of distilled water to ensure all the acid is transferred to the flask.
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Label and store: Label the flask with the solution's concentration (0.1 N H2SO4) and the date of preparation. Store the solution in a cool, dark place, away from direct sunlight and heat sources.
Tips and Precautions
- Always handle concentrated sulfuric acid with caution, wearing protective gloves, goggles, and a lab coat.
- When diluting the acid, add the acid to the water, not the other way around, to prevent splashing and potential explosions.
- Use a fume hood or a well-ventilated area to prepare the solution to avoid inhalation of sulfuric acid fumes.
- Dispose of any waste acid and rinse water according to local regulations and laboratory protocols.
By following these steps, you can prepare a 0.1 normal solution of sulfuric acid, which can be used in various laboratory applications. Always handle the acid with caution and follow proper laboratory protocols to ensure a safe working environment.
