Write the reaction between hydrogen and oxygen.

Hint: The reactions between hydrogen and oxygen are found to form new compounds, water and hydrogen peroxide. These reactions occur at different conditions of temperature and pressure with different catalysts.

Complete answer:
At normal temperature, hydrogen and oxygen gases interact without causing a chemical reaction. This is due to the fact that the speed of the molecules does not generate enough kinetic energy to ignite the reaction when the reactants collide. A gas combination is generated, which has the potential to violently react if enough energy is added to it.
Hydrogen and oxygen can react in two ways:
In the first method, hydrogen and oxygen react to form water. This reaction takes place in the presence of an electric spark. To disrupt the covalent bonds in hydrogen and oxygen molecules, energy must be given. Because of their electronegativity discrepancies, the hydrogen cations and oxygen anions are free to react with one other. Additional energy is released as chemical bonds re-form to produce water, which propagates the reaction.
$2{H_2} + {O_2} \to 2{H_2}O$
In the other reaction, hydrogen and oxygen combine to form Hydrogen peroxide.
${H_2} + {O_2} \to {H_2}{O_2}$

Note:
The reactants, in this case hydrogen and oxygen, have a higher energy level than the reaction products, as with other fuels. An exothermic reaction is one in which there is a net release of energy from the process. The energy produced by one set of hydrogen and oxygen molecules causes molecules in the surrounding mixture to react, releasing more energy. As a result, an explosive, fast-moving reaction occurs, releasing energy in the form of heat, light, and sound.