Q.A commercial sample of hydrogen peroxide marked as 100 volume H₂O₂, it means that

Hydrogen peroxide is manufactured industrially chiefly by the auto-oxidation of a 2-alkylanthraquinol (commonly 2-ethylanthraquinol) with air or oxygen, which produces $H_2O_2$ along with the corresponding anthraquinone; the anthraquinone is then regenerated back to the quinol by catalytic hydrogenation, so the organic carrier is recycled continuously. In the laboratory it can also be obtained by acidifying barium peroxide, or by treating sodium peroxide with dilute acid. Structurally, $H_2O_2$ is a non-planar molecule often described as having an 'open book' or skew shape: each oxygen atom is $sp^3$ hybridised, bonded to one hydrogen and to the other oxygen through a single, relatively weak O–O (peroxide) linkage, and the dihedral angle between the two O–H bonds differs between the gas phase (about $90.2^\circ$) and the solid phase (about $99.5^\circ$) owing to differing hydrogen-bonding environments in the two states. This is a key structural difference from water, $H_2O$, which is a simple triatomic molecule with only two O–H bonds and no O–O linkage; the extra, comparatively weak O–O bond in $H_ …