The 3% mass/volume H₂O₂ means 3 g of H₂O₂ in 100 ml of water.
Now, Molarity (M) = No. of moles of H₂O₂ / Volume of solution in liter
No. of moles of H₂O₂ = Mass / Molar mass = 3 g / 34 g/mol = 0.088 mol
So, molarity = 0.088 × 1000 ml / 100 ml = 0.88 M
In case of 2.25 % H₂O₂,
No of moles = 2.25 g / 34 g/mol = 0.066 mol
Molarity = 0.066 mol / 0.100 L = 0.66 M.
