Properties of Ozone

Physical properties of ozone: Ozone is a light blue colored gas, having pungent odor. It is heavier than air. Its vapor density is 24. It is slightly soluble in water.
Chemical properties of ozone: The important chemical properties of ozone are discussed below,
(1) Decomposition : Pure ozone decomposes on heating above 475 K to form O2 gas.
475 K
2O3 ————> 3O2 ΔH = –285.4 kJ
(2) Oxidizing agent :Ozone is one of the most powerful oxidizing agent with the liberation of dioxygen. In fact, ozone is a stronger oxidizing agent than molecular oxygen because ozone has higher energy content and decomposes to give atomic oxygen as:
O3 —> O2 + O
Atomic oxygen
Therefore, ozone oxidizes a number of non-metals and other reducing agents. e.g.
2Ag + O3 —> Ag2O + O2 ; S + 3O3 —> SO3 + 3O2
Metal Silver oxide Non-metal
PbS + 4O3 —> PbSO4 + 4O2
Compound
Mercury is oxidized to mercurous oxide,
2Hg + O3 —> Hg2O + O2
Mercurous oxide
During this reaction mercury loses its meniscus and starts sticking to the sides of the glass. This is known as tailing of mercury. Mercurous oxide formed in this reaction dissolves in mercury and starts sticking to the glass surface.
(3) Bleaching agent : Due to the oxidizing action of ozone, it acts as a mild bleaching agent as well as a sterilizing agent. It acts as a bleaching agent for vegetable coloring matter.
Vegetable colouring matter + O3 —> Oxidised coloured matter + O2
(Colourless)
For example, ozone bleaches indigo, ivory, litmus, delicate fabrics etc.
(4) Formation of ozonides : Ozone reacts with alkenes in the presence of CCl4 to form an ozonide. e.g.

Ethylene ozonide