Expert: George Maxwell - 9/4/2007

Question
hi, i need to know the difference between hydrogen peroxide solution 10 vol. and hydrogen peroxide solution 3% ... thank you

Answer
Hi, and thank you for your question.

Easy answer: they're the same! Vol and % are just different ways of measuring concentration.

3% Hydrogen Peroxide solution has 3 parts Hydrogen Peroxide to 97 parts water.

However, because hydrogen peroxide decomposes readily in to water and oxygen, another way of measuring the strength of a solution is to measue how much oxygen it gives off when it decomposes.

In the case of a 3% solution, 1 volume of hydrogen peroxide gives off 10 volumes of oxygen when it breaks down (e.g. if you start with 1 cm3 H2O2 you get 10cm3 of O2). For this reason, 3% H202 is sometimes called 10 vol H2O2. More concentrated solutions have correspondingly higher 'vol' numbers.

In summary, vol and % are different ways of measuring the strenght of H2O2, and 3% is the same as 10-vol.

Thanks for the question.