Re: my question is how could we balance Oxygen or any diatomic molecules as fraction i mean if we can balance oxygen in odd number what happen to other mono oygen atom and could that happen
That is really more of an algebra question than a chemical one. You need to find the "least common denominator" of the fractional atoms that you are balancing on both sides of an equation. In nature the combinations are of course always whole numbers of units. However, some compounds can have very strange numbers of different atoms in the combination!