A solution of H2O2 is labelled as 20 volumes. calculate the concentration in percent and normality
Answers
Volume strength refers to the number of volumes of oxygen gas evolved by one volume of H2O2. Now, 1.5 N of H2O2 will contain 1.5 equivalents of H2O2 per litre. 1.5 equivalents of H2O2 means 1.5/2 = 0.75 moles of H2O2.
Answer :- Concentration - 6%, Normality = 3.57N
When a dilute solution of hydrogen peroxide, H₂O₂ is labelled as 20 volume, what it implies is that 1 litre of H₂O₂ solution would produce 20 litre of oxygen.
Thus may be based on the equation 2H₂O₂ ------> H₂O+ O₂
Thus we say that 20 volume of H₂O₂
gives 68/22400 x 20 = 0.06 g
which translates to 6%.
1 litre of H₂O₂ solution would produce 20 litre of oxygen.
2 x 34 = 68
∴ 22.4L of O₂ will prepare 68L of H₂O₂
Hence 20L of O₂ will prepare = 68 x 22.4 / 20 = 60.71 g of H₂O₂
Moles of H₂O₂ = Mass/ Mole Mass
Moles of H₂O₂ = 60.71/34 = 1.78 moles
Molarity = number of moles / Volume
Molarity = 1.78 / 1 = 1.78M
Equivalent Mass = Molar Mass / 2
Equivalent Mass = 34/2 = 17
Normality = Mass/(Equivalent Mass x Volume)
Normality = 60.71/(17 x 1)
Normality = 3.57N