How does hydrogen react with oxygen to form water?

Hydrogen reacts with oxygen to form water through an exothermic chemical reaction represented by the equation $2H_2+O_2\to 2H_{2}O$.12

In this process, the constituent atoms of the reactants are rearranged to create new bonds, releasing energy as heat. While this reaction is product-favored, it does not occur spontaneously at room temperature because the reaction rates are negligible due to the high dissociation energy required to break the bonds in the hydrogen molecules.21

To initiate the reaction, the mixture must be heated to temperatures above 300° C, with ignition typically occurring between 550°–600° C. Alternatively, the reaction can be triggered by a spark, flame, or the presence of a catalyst. Mixtures containing 4 to 94 percent hydrogen are flammable, and a 2:1 mixture of hydrogen and oxygen is particularly explosive. Once the reaction proceeds, the resulting water molecule consists of two hydrogen atoms bonded to a single oxygen atom at an angle of 104.5°.13