How is strength of hydrogen peroxide expressed? Calculate the strength of 20 volume hydrogen peroxide in grams per litre.
Strength of hydrogen peroxide:
(i) As percentage. It is expressed as W/V percentage of H2O2 in solution. Thus, 30% solution of H2O2 means 30 grams of H2O2 are present in 100 ml of solution.
(ii) In terms of volume. The strength of hydrogen peroxide is expressed in terms of volume i.e. the bottles containing hydrogen peroxide are generally marked as 10 volumes or 20 volumes or 30 volumes etc. A solution of hydrogen peroxide labelled as 20 volume actually means that 1 ml of hydrogen peroxide solution on decomposition by heat produces 20 ml of oxygen at NTP.
Let us now calculate the strength of 20 volume H2O2 in gram/litre.
Hydrogen peroxide decomposes on heating as:
