Ammonia reacts with oxygen gas when heat is supplied and ammonia is oxidized as a result. Also this reaction occurs with catalyst and without catalyst under different conditions and you will learn everything about these reactions in detail in this tutorial.
At the end of this tutorial, you should know,
With supply of heat, ammonia reacts with oxygen and produce nitrogen gas and water as products. Nitrogen of ammonia is oxidized to nitrogen gas from -3 oxidation state to 0 oxidation state.
4NH3(g) + 3O2(g) → 2N2(g) + 6H2O(g)
Both ammonia and nitrogen gas are colorless gases. But their characteristics are so different.
In this reaction, ammonia is oxidized to nitric oxide (NO) and oxygen is reduced to water. Oxidation number of nitrogen is increased from -3 to +2. This is the first reaction of nitric acid production.
This reaction is a exothermic reaction and it emits -904 kJ mol-1. This is a very large amount of heat and it is an advantage to continue the reactions furthermore to manufacture nitric acid,
4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g)
Released nitric oxide readily converts to nitrogen dioxide, a brown colour and very toxic gas.
2NO(g) + O2(g) → 2NO2(g)
This reaction is used in ostwald process which produces nitric acid from ammonia. In that process, higher temperature is also used to increase the reaction rate to get the yield in a short time.
With solid CuO and supply of heat, ammonia is oxidized to nitrogen gas and CuO is reduced to copper. Copper oxide (CuO) is a black solid and produced copper has red-brown color.
3CuO(s) + 2NH3(g) → N2(g) + Cu(s) + 3H2O(l)
So CuO does not show a catalytic behavior with ammonia gas because amount of CuO is reduced when reaction is in progress. So Cu and CuO behave differently with ammonia.
Questions
Ask your chemistry questions and find the answersIf ammonia burns in oxygen at room temperature, nitrogen gas and water are formed when there is no catalyst. To oxidize nitrogen to nitric oxide, there should be high temperature. But, room temperature is not enough to do that oxidation process.
First think I should ask is, why do you use NH3 to generate power? There are so many fuels you can use for power generation. NH3 + O2 reaction gives lot of energy if it is used to henerate electricity. But, it is a waste because ammonia is much valuble than a fuel.
This method is used to oxidize NH
Without catalyst, ammonia is only oxidized to nitrogen gas. But in the presence of platinum catalyst, ammonia is oxidized to nitric oxide.
If ammonia react with oxygen without catalyst, nitrogen and water are given. Both compounds are not toxic.
Whem ammonia react with oxygen in the presence of Pt catalyst, nitric oxide (NO) and watwe are given. At levels of 100 ppm, nitric oxide is immediately dangerous to life and health.
Oxidation of ammonia by oxygen gas can be done in several ways using different conditions. According to the reaction conditions, products also vary.
WHen ammonia is oxidized by oxygen, oxidation number of N in NH3 increases from -3 to a higher higher oxidation number such as 0 or +2. O oxidation number is for N2 gas and +2 for NO gas.
Ammonia is a hazardous gas and very toxic to humans. So when this reaction is conducted, ammonia should be handled very carefully to prevent any leakages to outside environment.
One of my friend told, ammonia is oxidized by silver oxide (Ag2O). Is this true? If it is possible, how it happens?
Yes. Ammonia gas can be oxidized to nitrogen gas by silver oxide. Silver oxide is not stable to heat and decomposes. When silver oxide is heated, oxygen gas and silver metal are given as products.
With produced oxygen gas, ammonia is oxidized as before seen in the tutorial.
Oxidation of ammonia in the presence of catalyst by oxygen gas to NO and furthermore oxidation of NO to NO2 by oxygen gas is used in nitric acid production.
4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g)
2NO(g) + O2(g) → 2NO2(g)
2NO2(g) + H2O(g) → HNO3(aq) + HNO2(aq)
Hydrogen atoms combines with oxygen gas and produce water. Oxidation number of hydrogen does not change in this reaction. In the reaction of hydrogen sulfide and sulfur dioxide, oxidation number of hydrogen in H2S does not change.
Exothermic reactions gives products which have less energy than reactants. When energy of a compound is low, that increases the stability. Therefore, rather than being ammonia and oxygen, they like to react with each other to produce low energy compounds.
Ammonia and oxygen reaction release very large heat and it is helpful to do furthermore reactions.
Electronegativity of nitrogen is higher than hydrogen. So electrons of three N-H bonds are attacked towards nitrogen atom. So oxidation number of nitrogen in ammonia is +3.