Final answer:
Ammonia reacts with water to produce ammonium ions (NH₄⁺) and hydroxide ions (OH⁻). This process is an acid-base reaction where ammonia acts as a base and water as an acid. Changing the pH or adding a strong acid can increase the percent of ammonia that converts to ammonium ions. The correct option is 2.
Step-by-step explanation:
Ammonia reacts with water to form ammonium ions (NH₄⁺) and hydroxide ions (OH⁻). This reaction is an example of an acid-base reaction where ammonia (NH₃) acts as a base by accepting a proton (H⁺) from a water molecule, thus water acts as the acid. In this reaction, the conjugate acid-base pairs are NH₄⁺/NH₃ and H₂O/OH⁻. Under typical conditions, only a small percentage of the dissolved ammonia is present as NH₄⁺ ions.
To increase the percent of ammonia converted to the ammonium ion, changes in the reaction conditions, such as a decrease in the pH, could be effective. This is because lowering the pH would increase the concentration of H⁺ ions in the solution which would drive the forward reaction, converting more NH₃ to NH₄⁺. Adding a strong acid to the solution is one way to achieve this.
Hence, option 2 is correct.