Ammonia and Chlorine Reaction | NH3 + Cl2

Ammonia and chlorine gasreacts in two ways according to the amount of reactants (ammonia and chlorine). If there is excess ammonia, given products are different than given products when there is excess chlorine. Both chlorine and ammonia in gaseous state.

Inorganic chemistry, ammonia and chlorine gas reaction



Reaction Types of Ammonia and Chlorine

  • Excess ammonia with less chlorine reaction
  • Less ammonia with excess chlorine reaction

Excess ammonia with less chlorine reaction

This reaction occurs in two steps to give final products. A redox reaction (oxidation redox reaction) is occurred.

  1. First, ammonia reacts with chlorine and produce nitrogen gas and hydrogen chloride vapor. Produced hydrogen chloride vapor can behave as an acidic compound (can release H+ ions in the water).
  2. Then, hydrogen chloride reacts with basic ammonia gas to produce ammonium chloride which is a solid white smog. To happen this second step reaction, ammonia is required. That's why required amount of ammonia is high.

2NH3 + 3Cl2 = N2 + 6HCl

NH3 + HCl = NH4Cl


Balanced equation

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.


ammonia and chlorine gas reaction

How to balance NH3 + Cl2 = N2 + NH4Cl

We are going to discuss how to balance the chemical equation when excess ammonia reacts with chlorine.

  • First, find the oxidation numbers of each element in the right and left side of the reaction. You will find that, oxidation numbers of nitrogen and chlorine are changed. (discussed in earlier)
  • Equalize the oxidizing and reducing atoms before redox balance is done. There are two nitrogen atoms in right side (not count nitrogen in NH4Cl because nitrogen in NH4Cl oxidation number is -3). So make two ammonia molecules to equalize number of nitrogen atoms.
  • To balance chlorine atoms, make two NH4Cl because there are two chlorine atoms initially in the left side.
  • Now, take the oxidation numbers difference in oxidation reaction and reduction reaction. Then exchange with each other. For that, differences are 6 and 2 for nitrogen and respectively. 6:2 is taken as 3:1. After exchanging, equation should be like this.
  • 2NH3 + 3Cl2 = N2 + 3*2NH4Cl
  • Nitrogen atoms are not equal now. Eight nitrogen atoms are in right side and only two in left. So make four nitrogen molecules to balance number of nitrogen atoms.
  • Number of hydrogen atoms is also balance now.


Less ammonia with excess chlorine reaction

Ammonia reacts with chlorine and produce nitrogen trichloride (NCl3) and hydrogen chloride vapor. This reaction is also a redox reaction.

Balanced equation

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.

NH3 + Cl2 = NCl3 + HCl

How to balance NH3 + Cl2 = NCl3 + HCl reaction

We are going to discuss how to balance the chemical equation when ammonia reacts with excess chlorine gas.

  1. Find oxidation numbers of nitrogen, hydrogen and chlorine atoms. You see, only oxidation number of chlorine atoms are changed while nitrogen's and hydrogen's are kept same in left side and right side. Chlorine's oxidation number is changed from 0 to -1 and +1.
  2. Then, equalize number of atoms which are oxidized and reduced. Here, only chlorine atoms should be considered. In right side, there are four chlorine atoms and two chlorine atoms in left side. Add one chlorine molecule to left side. Now number of chlorine atoms are same in both side.
  3. Now determine the oxidation number difference and reduction number difference. Oxidation number difference in oxidation is 3. Reduction numbers difference in reduction is 1. Then exchange the differences.
  4. Then you will get the balanced equation.

This type of redox reaction balancing example is reaction of chlorine gas with sodium hydroxide.


Safety Precautions

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.


Ammonia

  • Flammable gas
  • Toxic if inhaled - produces respiratory reflexes such as coughing and arrest of respiration.
  • Causes severe skin burns and eye damage
  • Toxic to aquatic life

Chlorine gas

  • May cause to intensity fire
  • Can be oxidized
  • Causes severe skin burns and eye damage
  • If inhaled, can be fatal
  • Toxic to aquatic like


Questions


When 6 moles of ammonia reacts with 3 moles of chlorine, which products are given?

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.


first step

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.

second step

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.



If you want do cl2 + nh3 excess reaction, exactly, how would you mix reactants?

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.



What are the products when excess iodine and ammonia are reacted?

Nitrogen triiodide (NI3) is given as the product.



what are observation when ammonia reacts with Chlorine gas

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.



What will happen when NCl3 is hydrolyzed?

NCl3 is hydrolyzed to NH3 and HOCl. With intermediate formation of hydrogen bonds species.

NCl3 + 3H2O → NH3 + 3HOCl


NH3 and HCl redox?

NH3 and HCl reaction is not a redox reaction.

ammonia gas and hydrogen chloride gas equation

NH3 + HCl → NH4Cl





References

  1. Nitrogen trichloride
  2. MATERIAL SAFETY DATA SHEET (MSDS) AMMONIA




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