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What type of reaction takes place when ammonia and hydrogen chloride gases are mixed?

Published in Chemical Reaction Type 2 mins read

When ammonia (NH₃) and hydrogen chloride (HCl) gases are mixed, a neutralization reaction takes place. This is a classic example of an acid-base reaction in chemistry.

Understanding the Reaction

The reaction between ammonia gas and hydrogen chloride gas is a straightforward chemical process. It involves the interaction of an acid and a base, resulting in the formation of a salt.

Acid-Base Interaction

As stated in the reference, the reaction between ammonia (NH₃) and hydrogen chloride (HCl) gases is a classic example of a chemical reaction called a neutralization reaction. In this reaction, an acid (hydrogen chloride) reacts with a base (ammonia) to form a salt and water.

In this specific gas-phase reaction:

  • Hydrogen chloride (HCl) acts as the acid. It is a strong acid when dissolved in water, but even as a gas, it readily donates a proton (H⁺).
  • Ammonia (NH₃) acts as the base. It is a weak base that can accept a proton (H⁺).

Formation of Ammonium Chloride

The product of this reaction is a solid salt called ammonium chloride (NH₄Cl). This salt is formed by the combination of the ammonium ion (NH₄⁺), which is created when ammonia accepts a proton, and the chloride ion (Cl⁻), which is left when hydrogen chloride donates a proton.

The chemical equation for this reaction is:

NH₃(g) + HCl(g) → NH₄Cl(s)

When these two gases mix, a dense cloud of white fumes is often observed. These fumes are tiny solid particles of ammonium chloride forming in the air.

Key Aspects of the Reaction

  • Type: Neutralization (specifically, a Lewis or Brønsted-Lowry acid-base reaction resulting in a salt).
  • Reactants: Ammonia gas (NH₃) and Hydrogen Chloride gas (HCl).
  • Product: Solid Ammonium Chloride (NH₄Cl).
  • Observation: Often produces visible white fumes (solid NH₄Cl particles).

Summary Table

Component Formula Role in Reaction
Ammonia (Gas) NH₃ Base
Hydrogen Chloride (Gas) HCl Acid
Ammonium Chloride (Solid) NH₄Cl Salt

This reaction demonstrates a fundamental principle in chemistry: acids and bases react to neutralize each other, forming a salt. While the general definition of neutralization often includes water formation, in the gas-phase reaction between NH₃ and HCl, the product is the solid salt without the direct formation of water.