Preparation of a 10 M Sulfuric Acid Solution from a Concentrated Stock

When dealing with concentrated sulfuric acid (H2SO4), it is crucial to handle it with care as it is highly corrosive and extremely reactive. The strength of the concentrated sulfuric acid is often around 98%, which means it has a high concentration of sulfuric acid. This article will guide you through the process of preparing a 10 M solution of sulfuric acid from this stock solution.

General Guidelines for Handling concentrated H2SO4

The first and foremost principle is to always add acid to water. Never add water to acid due to the risk of a violent reaction that could cause splashing and harmful chemical burns. This rule is important for safety and to avoid the generation of excessive heat that could lead to boiling over or splashing. In this scenario, you are starting with a concentrated sulfuric acid solution that is approximately 18 Molar (M) with respect to hydronium ions (H3O ), which translates to about 36 Molar with respect to sulfuric acid (H2SO4).

Preparation of the 10 M Sulfuric Acid Solution

To prepare a 10 M sulfuric acid solution, you will need to add a certain volume of concentrated sulfuric acid to a larger volume of distilled water. The exact volumes will depend on the density of the stock solution. For most practical purposes, a 10–times dilution is a significant drop in concentration, reducing the Molarity from around 18 M to 1.0 M.

Here is a step-by-step guide to carry out this preparation:

Step 1: Gather Equipment and Personal Protective Equipment (PPE)

Personal protective equipment (PPE) such as gloves, safety goggles, and appropriate laboratory clothing. A volumetric flask of the desired final volume (e.g., 1 liter for a 1 L solution). A measuring cylinder or pipette for accurate volume measurements. The concentrated sulfuric acid. Distilled water.

Step 2: Calculate the Required Volumes

Based on the dilution factor, you can calculate the volumes needed. For a 10 M solution, you need to dilute the concentrated sulfuric acid to a 1:10 ratio. Assuming you are making 1 liter of the 10 M solution, you need:

10 mL of concentrated sulfuric acid. 990 mL of distilled water.

Use a measuring cylinder or pipette to measure these volumes accurately.

Step 3: Mix the Solutions

Pour the measured concentrated sulfuric acid into the volumetric flask. Slowly and carefully add the distilled water while continuously swirling the flask to ensure a uniform mixture. Vigorously swirling the solution will help to distribute the acid uniformly and minimize the risk of a violent reaction.

Step 4: Label and Store the Solution

Once the solution is mixed, label the volumetric flask with the concentration, date, and any safety information. Store the solution in a cool, well-ventilated area away from heat sources or other reagents.

Measuring pH and Ensuring Correct Concentration

After completing the preparation, it is essential to measure the pH of the solution to confirm its concentration. You can use a pH meter or pH paper to measure the acidity. The pH of a 10 M sulfuric acid solution should be around 0.7 (pH -log[H ]), which corresponds to a concentration of 1.0 M with respect to H3O .

Additionally, you can perform a titration using a known base (such as sodium hydroxide) to verify the concentration. This method is more accurate and can help you identify any discrepancies in the calculated volumes.

Conclusion

Preparing a 10 M sulfuric acid solution from a concentrated stock is a straightforward process when handled carefully. By following the guidelines provided, you can ensure a safe and accurate preparation. Always remember to add acid to water and perform all operations in a well-ventilated area with appropriate PPE.

Keywords

Concentrated Sulfuric Acid, Preparation of Acid Solution, pH Measurement