Question

Hydrogen reacts explosively with oxygen. However, a mixture of \(\mathrm{H}_{2}\) and \(\mathrm{O}_{2}\) can exist indefinitely at room temperature. Explain why \(\mathrm{H}_{2}\) and \(\mathrm{O}_{2}\) do not react under these conditions.

Short answer

At room temperature, hydrogen and oxygen do not react spontaneously due to insufficient ambient energy, improper conditions for collision according to the collision theory, and the absence of a catalyst. These factors prevent the gases from overcoming the activation energy required to initiate the explosive reaction, thus allowing them to coexist indefinitely.

Step-by-step solution

Activation Energy

In order for a chemical reaction to occur, the reactants must overcome a certain energy threshold known as the activation energy. Activation energy is the minimum energy required to initiate a chemical reaction, and the Ambient energy at room temperature might not be enough to reach this activation energy level. Consequently, Hydrogen and Oxygen can exist together at room temperature without reacting spontaneously.

Collision Theory

According to the collision theory, a chemical reaction occurs when reactant particles collide with the appropriate orientation and with enough energy to break and form new bonds. At room temperature, the gas molecules may not collide frequently or forcefully enough to initiate the reaction between Hydrogen and Oxygen.

Reaction Catalyst

In many chemical reactions, the presence of a catalyst greatly influences the rate of reaction. A catalyst lowers the activation energy required for a reaction to occur, making it easier for the reactants to overcome the energy barrier. In the case of the reaction between Hydrogen and Oxygen at room temperature, there may be no catalyst present, resulting in the lack of spontaneous reaction between the two gases. To summarize, at room temperature, the lack of sufficient ambient energy, proper conditions for collision, and catalyst presence are factors that prevent Hydrogen and Oxygen from reacting explosively, allowing them to coexist indefinitely.