Understanding Hydrogen Peroxide Concentrations: Mixing Water and 60% H2O2

Hydrogen peroxide, a common disinfectant and bleaching agent, is often used in various applications. A common question arises: What happens when you mix a 60% solution of hydrogen peroxide with water? Does mixing half water and half 60% hydrogen peroxide give you a 30% solution?

Concentration of Hydrogen Peroxide

A 60% solution of hydrogen peroxide means that in 100 mL of this solution, there are 60 mL of hydrogen peroxide. This percentage concentration is a measure of the solute (hydrogen peroxide) by volume relative to the total volume of the solution.

Mixing Equal Volumes of Water and 60% Hydrogen Peroxide

Let's consider mixing equal volumes of water and a 60% hydrogen peroxide solution. For simplicity, we'll use 100 mL of each.

Step 1: Calculate the hydrogen peroxide content in the 60% solution.

In 100 mL of 60% hydrogen peroxide, you have 60 mL of hydrogen peroxide.

Step 2: Calculate the hydrogen peroxide content in water.

Water contains no hydrogen peroxide, so there is 0 mL of hydrogen peroxide in 100 mL of water.

Step 3: Calculate the total volume of the mixture.

Total volume 100 mL (hydrogen peroxide) 100 mL (water) 200 mL.

Final Concentration Calculation

The concentration of the final solution can be calculated using the formula:

[ text{Concentration} left(frac{text{Volume of Hydrogen Peroxide}}{text{Total Volume}}right) times 100 ]

[ text{Concentration} left(frac{60 text{ mL}}{200 text{ mL}}right) times 100 30% ]

Therefore, mixing half water and half 60% hydrogen peroxide will result in a 30% hydrogen peroxide solution, not a 3% solution.

Note: To achieve a 3% solution, you would need to mix 1 part hydrogen peroxide with 19 parts water. This is a much more diluted solution compared to the 30% solution.

General Formula for Concentration of Solutions

If you have V1 mL of a C1% solution and V2 mL of a C2% solution, the final concentration C of the mixture can be calculated as:

[ C left(frac{V_1 times C_1 V_2 times C_2}{V_1 V_2}right)% ]

For example, if you mix 10 mL of a 60% solution with 10 mL of a 0% solution (water), the calculation would be:

[ frac{[10 times 60 10 times 0]}{10 10} frac{600}{20} 30 % ]

This confirms that mixing equal volumes of a 60% hydrogen peroxide solution and water results in a 30% solution.

Additional Considerations

When dealing with hydrogen peroxide, it's important to consider its properties and potential hazards. Hydrogen peroxide decomposes over time, releasing oxygen and water, which can make the solution less stable. Mixing concentrated solutions may generate heat, so proper ventilation and caution are advised.

Conclusion: Mixing half water and half 60% hydrogen peroxide will give you a 30% hydrogen peroxide solution, not a 3% solution.