Final answer:
The product formed when a proton reacts with ammonia (NH3) is the ammonium ion, NH4+.
Step-by-step explanation:
In the chemical reaction between a proton and ammonia (NH3), ammonia functions as a Brønsted-Lowry base, showcasing an acid-base reaction. In this process, ammonia accepts a proton (H+) from a water molecule, leading to the formation of the ammonium ion (NH4+), its conjugate acid. This interaction exemplifies the fundamental concept of acid-base reactions, characterized by the transfer of protons between substances. The ability of ammonia to act as a base, accepting a proton, highlights its role in the dynamic equilibrium of chemical systems, contributing to our understanding of the principles governing proton transfer reactions in aqueous solutions.