When hydrochloric acid (HCl) reacts with ammonium hydroxide (NH₄OH), it's a neutralization reaction that produces ammonium chloride (NH₄Cl) and water (H₂O).

The reaction is exothermic.

Here's why:

* Neutralization Reactions: Neutralization reactions involve the reaction of an acid and a base, releasing heat. This is because the formation of the salt (ammonium chloride in this case) and water is a more stable state than the separate acid and base.

* Heat Release: The heat released during the reaction is the driving force behind the process. You would likely observe an increase in temperature if you were to mix these solutions.

Chemical Equation:

HCl (aq) + NH₄OH (aq) → NH₄Cl (aq) + H₂O (l) + Heat

Important Note: While ammonium hydroxide is often used as a term, it's important to understand that it doesn't exist as a distinct compound in solution. Ammonium hydroxide is actually ammonia (NH₃) dissolved in water.