Question

Do you expect the detonating reaction between hydrogen gas and oxygen gas forming water vapor (oxyhydrogen reaction) to have a temperature limit above or below which the reaction will not be spontaneous? Explain your answer and estimate such temperature from thermodynamic data found online.

2. (2 pts) Do you expect the detonating reaction between hydrogen gas and oxygen gas forming water vapor (oxyhydrogen reaction) to have a temperature limit above or below which the reaction will not be spontaneous? Explain your answer and estimate such temperature from thermodynamic data found online.

Answer 1

Firstly, detonating reactions are a kind of combustion reactions, this particularly includes a highly supersonic exothermic reaction that have different stages of explosions, and the graph plotted between logarithm of pressure and temperature would give us an explosion limit diagram. And a spontaneous reaction is a kind of reaction that favours or supports' forward reaction to form products.

Generally at room temperature, Oxygen and Hydrogen combine easily without any reaction, in order to react we have to give some external energy or activation energy for the reaction to run. But when the sufficient energy is given to ignite the reaction, they do react and form water molecules.

For all the given suitable situations, hydrogen and oxygen reacts very violently because the existing molecular bond will get broken and forms new bonds between hydrogen and oxygen molecules, which results is explosion of sudden energy burst and water is produced.

To be precise, the reactions that takes place in between hydrogen and oxygen are around 50 intermediary reactions. In which few reactions in all over the process adds up in increasing the free radicals in the mixture and few reactions be the rate determining steps of the intermediary reactions because of their high activation energy , that involves chain termination, and branching reactions. Few intermediary reactions are given below :

N H. + 02 - OH +0. O. + H₂ – OHot Ho [ki] [*₂] Hoo & H2 H₂O + Ho ! @ [kg] Ho + O2 + M HO₂+M [K4].

The dot represent those are free radicals. The Explosion limit diagram can be drawn between hydrogen and oxygen as follows :

Third L 오 Steady Reaction Log(P) (torr ] Second Limit Explosion First Limit 400 500 600 Temperature (°c)

When the temperature is around 400 deg.Celcius , the reaction between hydrogen and oxygen takes place in gaseous phase, and when the temperature is 600 deg.Celcius and above, the reaction is highly explosive and forms Oxyhydrogen or water vapour

Thank you !!