A buffered solution was created by mixing solutions of NH4Cl and NH3 at 25 C. Which species, NH4+ or NH3, has the highest concentration in this buffered solution?. Justify your answer.
This question can't be answered without know the pH of the solution. If you know the pH of the solution, substitute it into the Henderson-Hasselbalch equation and solve for the ratio of base to conjugate acid.
Well, let's see here. NH4Cl and NH3 are both involved in creating a buffered solution, but we want to figure out which species has the higher concentration. It's like trying to decide who the most popular clown at a circus is - tough choice!
When NH4Cl is dissolved in water, it dissociates into NH4+ and Cl-. And NH3 can also react with water to form NH4+ and OH-. So both NH4+ and NH3 are present in the solution, but NH4+ is produced from NH4Cl while NH3 is produced from both NH4Cl and the reaction with water.
Now, here's the funny part (I hope you're sitting down for this one): NH4+ is like that party-goer who keeps sticking to the group. It's produced directly from NH4Cl, so it's always there in a higher concentration compared to NH3.
On the other hand, NH3 is a bit of a wanderer. It's produced from both NH4Cl and the reaction with water, but it can also react with H+ ions to form NH4+. So, as NH4+ keeps piling up in the solution, some of the NH3 converts to NH4+ and the concentration of NH3 decreases.
In other words, NH4+ is the life of the party in this buffered solution! It's there in higher concentration than NH3 because it's directly produced from NH4Cl. So, if you're looking for the species with the highest concentration, go ahead and put on your NH4+ party hat!
To determine which species, NH4+ or NH3, has the highest concentration in the buffered solution, we need to consider the pH of the solution and the pKa of the ammonium ion (NH4+).
The buffered solution is formed by mixing NH4Cl and NH3, which is a classic example of an acid-base buffer. NH4Cl is a salt, and when dissolved in water, it dissociates into NH4+ and Cl- ions. NH3 is a weak base and acts as a conjugate base of NH4+.
In an acidic solution, NH4+ is favored because it can accept a proton (H+) from water, leading to the formation of NH3 and H3O+ (hydronium ion). In a basic solution, NH3 is favored because it can donate a proton (H+) to a hydroxide ion (OH-) present in water, leading to the formation of NH4+ and OH-.
At 25°C, the pKa of the ammonium ion (NH4+) is approximately 9.25. The pH of the buffered solution will determine the relative concentrations of NH4+ and NH3. If the pH is below the pKa, the concentration of NH4+ will be higher. If the pH is above the pKa, the concentration of NH3 will be higher.
Since we don't have the pH of the solution, we cannot definitively determine which species has the highest concentration in the buffered solution without that information.
To determine which species, NH4+ or NH3, has the highest concentration in the buffered solution, we need to consider the pH of the solution and the pKa of the NH4+/NH3 conjugate acid/base pair.
NH4Cl is a salt that dissociates in water to form NH4+ and Cl-. NH3 is the conjugate base of the ammonium ion NH4+. The pKa of the NH4+/NH3 conjugate acid/base pair is around 9.25 at 25°C.
In a buffered solution, the concentration of the weak acid and its conjugate base should be approximately equal for maximal buffering capacity. In this case, the NH4Cl has provided NH4+ and Cl-, while NH3 acts as the conjugate base.
At pH values near the pKa, the concentration of the weak acid and its conjugate base are equal. When the pH is lower than the pKa, the concentration of the conjugate acid (NH4+) is higher than the concentration of the conjugate base (NH3). When the pH is higher than the pKa, the concentration of the conjugate acid is lower than the concentration of the conjugate base.
Since the pKa of the NH4+/NH3 conjugate acid/base pair is around 9.25, at a pH lower than 9.25, NH4+ will have the highest concentration in the buffered solution. Therefore, NH4+ has the highest concentration in the buffered solution when NH4Cl and NH3 are mixed at 25°C.