How to prepare X% hydrogen peroxide solution from 33% H2O2 solution ?

Formulating

How to prepare X% hydrogen peroxide solution from 33% H2O2 solution ?

Posted by Roni on April 18, 2018 at 1:02 pm

Hello everyone,

I am new to the cosmetic formulation and I would be very happy if you would help me, as I ‘m not sure how to calculate:
I need to prepare a solution in which the hydrogen peroxide concentration will be 2.5%.
I also need to add to the final solution 10% of another ingredient.
I have 33% hydrogen peroxide.

thanks 🙂

em88 replied 6 years, 9 months ago 4 Members · 8 Replies
8 Replies

OldPerry

Professional Chemist / Formulator
April 18, 2018 at 1:20 pm

So you need a formula of water, ingredient X, and hydrogen peroxide.

To make 100 grams total (or 100%)

Hydrogen peroxide = 2.5%/33% = 7.57 g
Ingredient X = 10 g
Water = 82.43 g
Roni

Member
April 18, 2018 at 2:48 pm
thanks!
I was thinking to use the formula C1V1=C2V2
where C1 is a concentration of the stock solution (33%),
V1 is a volume which I require,
C2 is concentration which I want to make (2.5%)
and V2 is the volume which I want to make.

for example, if I want to make 100mL of 2.5% H2O2 from 33% H2O2. I use this formula and I will find that I need to add 90.91 mL distilled water to 9.09 mL of 33% H2O2.
and because I need to add 10g of ingredient X, the water I will add will be 80.91 mL.
The result I got is inaccurate
belassi

Member
April 18, 2018 at 4:59 pm

Be very careful around 33% H2O2, it is easy to inadvertently create high explosives.
Roni

Member
April 18, 2018 at 6:03 pm

Ok, I’ll be careful. Do you have anything to say about my wrong calculation?
belassi

Member
April 18, 2018 at 6:43 pm

Rule of 1, or 100%.
for example, if I want to make 100mL of 2.5% H2O2 from 33% H2O2.
Easy like this:

100mL of 2.5% solution: this is 2.5/100 multiplied by 100 or 2.5mL of H2O2 per 100mL. (97.5mL water + 2.5mL H2O2)
So you need to get 2.5mL of pure H2O2 from a 33% solution.
Well, if it were 100% solution you would need 2.5mL of it, right?
So you will need 2.5 x (100/33) mL of the 33% H2O2. Which is approx. 7.5mL of solution in 92.5mL water.
Roni

Member
April 18, 2018 at 8:11 pm

I think I understand now.
please let me be sure I’m on it:
if I want to make a 100 g solution with 8% concentration of ingredient X.
But the ingredient is not pure, the purity is 75%.
so I calculate it:
ingredient X = 8%/75% = 10.66 g
water = 89.34 g

correct?
belassi

Member
April 18, 2018 at 11:35 pm

Yes that’s it.
em88

Pharmacist
April 23, 2018 at 6:30 am

To prepare that 100g H2O2 2.5% solution:
C1V1=C2V2
33%*V1=2.5%*100
V1= (2.5%*100)/33%
V1= 7.58g H2O2 33%
Ingredient X = 10 g
Water = 100 - 7.58 - 10 = 82.42g