VOLUME STRENGTH OF H2O2(aq)

Hydrogen peroxide is a colourless liquid used as bleaching agent in some food and act as oxidising as well as reducing agent.

The most common use of hydrogen peroxide is in cosmetic including personal care, hair dye, bleach shampoos conditioners and first aid antiseptic.

Hydrogen peroxide also used as propellant for torpedoes on account of its exothermic decomposition.

The strength of Hydrogen peroxide expressed several ways like Volume strength, W/V % (% strength), Molarity, Normality etc.

 

COMMERCIAL LABELLING OF H₂O₂ AS ‘X’ VOLUME :  

Commercially H₂O₂ labelled as 'X' volume H₂O₂ 

(At P =1 ATM and T=273 K)
Where 'X' may be 10V, 20V, 30V, 40 V etc. 

Here 'X' Volume H₂O₂ means that 1ml of such solution of hydrogen peroxide on decomposition produce 'X' ml of oxygen (At P=1 ATM and T=273 K).

For example 10 Volume H₂O₂ means that 1ml of such solution of hydrogen peroxide on decomposition produce '10' ml of oxygen (at P=1 ATM and T=273 K).

 

w/v % or percentage strength of H₂O₂ solution: 

The amount of H₂O₂ in gram present in 100 ml of aqueous solution of H₂O₂. Called (w/v) or percentage strength.

 

Illustration:  taken 10 V (Vol) H₂O₂:

 

By Stoichiometric calculations:

Thus 1ml, 10 V labelled H₂O₂ (aq) solution contains 0.0303 gm H₂O₂.

Similarly 100 ml, 10 V labelled H₂O₂ (aq) solution contains 0.0303x100=3.03 gm of H₂O₂. This called W/V % or percentage strength of H₂O₂ solution.

 

Molarity and Normality of H₂O₂:

 And 1000 ml, 10 V labelled H₂O₂ (aq) solution contains 0.0303 x1000=30.30 gm H₂O₂. It means 30.30 gm H₂O₂ dissolved in 1000 ml (1L) Solution.

 

  Hence Molarity of 10 V H₂O₂ Solution is = 0.89 M

  Normality of 10v H₂O₂ (aq) Solution: 

Hence Normality of 10 V H₂O₂ Solution is =1.79 N

 We also know that 

NORMALITY = MOLARITY  X  n-FACTOR

     Normality = O.89 x 2 = 1.79 N

 

Alternative Method to determined Molarity and Normality:

Volume of O₂ provided by 1unit Volume of H₂O₂ aq Solution

illustrative examples:

EXAMPLE: (1) A solution of H₂O₂ has Normality N/1.7 calculate w/V strength of this solution?.

EXAMPLE: (2) Convert 20 V H₂O₂ into % strength or w/v strength?

EXAMPLE: (3) Convert 6.8 % strength of H2O2 into Volume strength?

EXAMPLE: (4) 500 ml of a H₂O₂ solution on decomposition produce 2 mole of H₂O. Calculate the Volume strength of of H₂O₂ of solution? (Given Volume of O2 measured at 1atm and 273 K)  (Ans - 44.8 V)

EXAMPLE: (5) What is the percentage strength of "15" volume of H₂O₂?
EXAMPLE: (6) What volume of H₂O₂ solution of "11.2 volume strength is required to liberate 2240 ml of O₂ at NTP?

EXAMPLE: (7) 30 gm Ba(MnO₄)₂ sample containing inert impurity completely reacting  with 100 ml "28" volume strength of H₂O₂ in acidic medium then what will be the percentage purity of Ba(MnO₄)₂ in the sample ?. (Ba=137, Mn = 55, O =16)

EXAMPLE: (8) the strength of "20 Volume" H₂O₂ is equal? 

EXAMPLE: (9) What is weight of available oxygen from a solution of H2O2, if 20 ml of this solution need 25 ml, N/20 KMnO4 for complete oxidation? (Ans- 0.25)

EXAMPLE :( 10) calculate molarity of 44.8 V strength of H₂O₂ aq Solution?.

EXAMPLE: (11) calculate the molarity of H₂O₂ if 11.2 ml H₂O₂ require 30 ml of 0.5 M K2Cr2O7 for its complete oxidation; also calculate the Volume strength of H₂O₂? (Ans M=45/11.2 and volume strength=45)