Question

hydrogen is combustion oxygen help combustion but water helps to extinguish fire

Answer 1

There is a difference between mixture and compound. At the end of chemical combination the form of substance changes completely. Its properties become different from the properties of the constituent elements. The constituent elements of a compound can not be separated easily. Accompanying diagram gives an idea of how an atom of oxygen bounds strongly with two atoms of hydrogen. Each atom of oxygen has six electrons orbiting around it but still has room for two more electrons. If suitable electrons of some other substance are available then oxygen accepts them and forms a permanent bond. A hydrogen atom has one such electron. Since it has only one electron, two atoms of hydrogen fill that gap with their two electrons. This bounding of atoms of oxygen and hydrogen elements creates a chemical H2O, i.e. water having entirely different properties. Bounded atoms of oxygen and hydrogen no longer retain their original properties.

Answer 2

hydrogen is a highly combustible substance while oxygen is a supporter of combustion but when the post method is chemical reaction and the boat combined form a new compound called water it has totally different properties you know what I can take out fire but as we know what happened is two atoms of hydrogen one atom of Oxygen they both are in a hydrogen is highly compressible why oxygen is supporter of combustion therefore we can see that from this question we can verify that if two elements combined together they can form a new compound that is totally different properties from that of its constituent appeal against