though ozone & oxygen are allotropes, why do they hava difference in chemical properties?

Question

allotropes have similar chemical properties

Answer 1

Unlike allotropes of carbon (diamond and graphite), the allotropes of oxygen have a different chemical formula: O2 and O3. O3 is a much more fierce oxidising agent than O2.
The allotropes of phosphorus also have very different chemical reactions, so I suspect that your generalisation is not true.

Answer 2

Not necessarily. In fact, many allotropes have markedly different properties: contrast shale to diamond, both alletropes of carbon or white and red phosphorous. As with the others, the answer lies in the bonding. O2 is O=O in bonding, while ozone is like an equilateral triangle with oxygens at the apexes. The bonds are strained, since the apex angles are 60 deg vs a normal angle of 109 degrees. It is much more reactive than oxygen, and by the reaction:
O3 -> O2 + O [momentarily], the ozone is a powerful biocide.

Answer 3

The word "allotrope" is something of a misnomer. It has been often suggested that the word be replace by poymorph (or others)

Allotropes do not in general have the same physical properties (e,g. graphite and diamond alotropes of carbon)
{not to mention Buckyballs, another allotrope of carbon}

Sulfer is another example, in fact I think dioxygen and Ozone may be as similar as any allotropes.

But why would they be the same, just because they contain the same element?
Just because they contain the same elements in the same proprtions?

Think of the difference between ethylene ( hydorcarbon gas)
and polyethylene (a liquid or (mostly) solid).
The physical properties depend on the molecular weight (and structure).

Answer 4

if youre wondering why ozone reacts with CFC's (chlorofluorocarbons) and oxygen doesn't, thats because the CFC's, when the reach the upper atmosphere, break into free radicals (species with a single electron, and hence highly reactive) by the effect of UV light, and these free radicals then attack the ozone layer. i hope this helped.

Answer 5

I like gervalds answer, also ozone (O3) is a bent molecule, making it polar, whereas O2 is linear and non-polar