Ammonia and chlorine gases react with each other in two ways according to the available amount of reactants (ammonia and chlorine) in the reaction mixture. If there is excess ammonia gas, given products are different from given products when there is excess chlorine gas. Both chlorine and ammonia in gaseous state in this reaction.
Inorganic chemistry, ammonia and chlorine gas reaction
There are possibilities for two reactions according to the amount of ammoni and chlorine gases. So different products will be given according to the reactions and we will discuss in detail in this tutorial.
This reaction occurs in two steps to give final products. A redox reaction (oxidation redox reaction) is occurred.
2NH3 + 3Cl2 = N2 + 6HCl
NH3 + HCl = NH4Cl
8NH3 + 3Cl2 = N2 + 6NH4Cl
You can see there are three chemical equations. First two of them are steps of the complete reaction and last reaction is the complete reaction. Complete reaction is made by adding two equations with multiplying second equation from 6 times. in addition of two reactions, HCl is cancelled out from complete reaction. So HCl is an intermediate product.
Due to redox reaction, oxidation numbers of reactants are important. In this reaction ammonia is oxidized to nitrogen from -3 to 0 and chlorine is reduced to chloride ion from 0 to -1.
Ammonia behave as a reducing agent while chlorine is a oxidizing agent.
We are going to discuss how to balance the chemical equation when excess ammonia reacts with chlorine.
Ammonia reacts with chlorine and produce nitrogen trichloride (NCl3) and hydrogen chloride vapor. This reaction is also a redox reaction.
2NH3 + 3Cl2 = 2NCl3 + 6HCl
Nitrogen trichloride is a yellow oily liquid with pungent odor.
In this reaction, chlorine is reduced and oxidized. So this is an disproportionation reaction. Oxidation number of chlorine (o) is changed to -1 and +1. No change of oxidation number of nitrogen when products are given.
We are going to discuss how to balance the chemical equation when ammonia reacts with excess chlorine gas.
This type of redox reaction
balancing example is reaction of chlorine gas with sodium hydroxide.
Here we look toxicity and injuries can be occurred due to using chemicals in this reaction. Study MSDS (material safety data sheets) before you conduct the experiment.
First, look two reactions can be occurred between ammonia and chlorine. Then check the amount of moles of reactants and decide what is the excess reactant.
We see there is excess ammonia in the reactants. If there is excess ammonia, nitrogen and ammonium chloride should be given as products. In that reaction, ratio between ammonia and chlorine is 8:3 . But in the given reactants, ratio of ammonia and chlorine is 6:3 .
Now we should see two steps of reaction between excess ammonia and chlorine.
2NH3 + 3Cl2 = N2 + 6HCl
From the stoichiometry, two ammonia moles and three chlorine moles are spent. So all chlorine are finished and four ammonia moles are remaining. As products one nitrogen mol and six HCl moles are given.
Now remaining four moles of ammonia can reacts with produced HCl.
NH3 + HCl = NH4Cl
Four HCl moles will reacts with remaining ammonia 4 moles and produce four ammonium chloride moles. Two HCl moles will remain as unreacted HCl.
Stoicheometry says us, what is the exact ratio reactants are reacted. In Cl2 and excess NH3 reaction, they react with 3:8 ratio. But, to complete a reaction, there are requirements. There should be atleast one excess reagent. So if there are three Cl2 moles, there should be more than eight moles of Cl2.
Nitrogen triiodide (NI3) is given as the product.
If amount of chlorine is high, you can see a brown colour oil (NCl3) is formed. Otherwise, ammonia is high, a white colour solid fog (NH4+Cl) is formed.
NCl3 is hydrolyzed to NH3 and HOCl. With intermediate formation of hydrogen bonds species.
NCl3 + 3H2O → NH3 + 3HOCl
NH3 and HCl reaction is not a redox reaction because oxidation numbers of atom of reactants are not changed when they give products.
NH3 + HCl → NH4Cl