When excess ammonia is treated with chlorine gas, a chemical reaction occurs yielding two main products: ammonium chloride and nitrogen gas. This specific reaction is crucial as it differs significantly from the reaction when chlorine is in excess.
The Chemical Reaction Explained
The reaction between excess ammonia (NH₃) and chlorine (Cl₂) results in the formation of solid ammonium chloride (NH₄Cl), which often appears as dense white fumes, and gaseous nitrogen (N₂).
This reaction is a redox reaction. Ammonia acts as a reducing agent, being oxidized to nitrogen gas, while chlorine acts as an oxidizing agent, being reduced to the chloride ion, which then combines with ammonia to form ammonium chloride.
Balanced Chemical Equation
According to the provided reference (July 3, 2022), the balanced chemical equation for the reaction of excess ammonia with chlorine is:
8 NH₃ (g) + 3 Cl₂ (g) ⟶ 6 NH₄Cl (s) + N₂ (g)
- NH₃: Ammonia (in excess)
- Cl₂: Chlorine gas
- NH₄Cl: Ammonium chloride (forms as a white solid/fumes)
- N₂: Nitrogen gas (liberated)
This equation shows that 8 molecules of ammonia react with 3 molecules of chlorine to produce 6 molecules of ammonium chloride and 1 molecule of nitrogen gas. The excess amount of ammonia is key to ensuring that all the chlorine reacts to form ammonium chloride and nitrogen, preventing the formation of explosive nitrogen trichloride (NCl₃), which occurs when chlorine is in excess.
Products of the Reaction
Let's look at the products formed:
- Ammonium Chloride (NH₄Cl): This is an ionic compound formed between the ammonium ion (NH₄⁺) and the chloride ion (Cl⁻). It's a white crystalline solid at room temperature but is often seen as white fumes when produced in this reaction due to sublimation or formation of fine particles. It is soluble in water.
- Nitrogen Gas (N₂): This is a diatomic molecule consisting of two nitrogen atoms. It is a colorless, odorless, and relatively inert gas that is the most abundant component of Earth's atmosphere.
Summary Table
| Component | Formula | Role in Reaction | Notes |
|---|---|---|---|
| Reactants | |||
| Ammonia (excess) | NH₃ | Reducing Agent | Gaseous reactant, supplied in excess |
| Chlorine | Cl₂ | Oxidizing Agent | Gaseous reactant |
| Products | |||
| Ammonium Chloride | NH₄Cl | Product | White solid/fumes |
| Nitrogen | N₂ | Product | Gaseous product |
Practical Insights
- The reaction of ammonia with chlorine is often used to demonstrate the difference in products based on limiting reactants. If chlorine were in excess, the highly explosive nitrogen trichloride (NCl₃) would be formed instead: NH₃ + 3 Cl₂ (excess) ⟶ NCl₃ + 3 HCl. This makes handling chlorine with ammonia potentially hazardous if the stoichiometry is not carefully controlled with excess ammonia.
- The formation of dense white fumes of ammonium chloride is a visual indicator of this reaction occurring.
In summary, the reaction of excess ammonia with chlorine produces ammonium chloride and nitrogen gas, as described by the balanced equation 8 NH₃ + 3 Cl₂ ⟶ 6 NH₄Cl + N₂.
