The balanced equation for an acid dissociation is:. In an alternate application, the equation can be used to determine the amount of acid and conjugate base needed to make a buffer of a certain pH. An example of how to use the Henderson-Hasselbalch equation to solve for the pH of a buffer solution is as follows:. What is the pH of a buffer solution consisting of 0.
The equation for the reaction is:. By using the fact that weak acids and bases barely ionize, allowing us to approximate the pH of buffer solutions using initial concentrations. Lawrence Joseph Henderson was a talented biochemist, among many other titles, who spent most of his career at Harvard. He was responsible for developing the components of the equation after studying equilibrium reactions that took place within blood as a result of respiration specializing in "fatigue".
His equation was incomplete without the solid calculations into it provided by Hasselbalch. Karl Albert Hasselbalch was a chemist who studied pH closely. He also studied blood and reactions that took place with oxygen, to put in the simplest of terms. And the hydrochloric acid is immediately used up upon addition into the solution.
The water is at a constant concentration so is not considered the predominant species. The first reaction that has to happen is the creation of , ammonium. We need to determine how many moles of hydrogen ions that we have from the HCl, that is equal to the amount of that is formed. First we need to determine how many moles we have of and.
The first reaction that will happen is the formation of acetate from the reaction of the strong base with acetic acid:. So the amount of acetate, formed is equal to the number of moles of added. So now that we know how many moles we have of the weak acid and its conjugate base, we can use the Henderson-Hasselbalch equation:.
Determine what volume of 0. We need to use the Henderson-Hasselbalch equation to determine how many moles of ammonia we need. If you've found an issue with this question, please let us know. With the help of the community we can continue to improve our educational resources. If Varsity Tutors takes action in response to an Infringement Notice, it will make a good faith attempt to contact the party that made such content available by means of the most recent email address, if any, provided by such party to Varsity Tutors.
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Possible Answers:. Correct answer:. Explanation : In this question, we're given the concentrations of both a weak acid and its conjugate base in solution. Report an Error. Example Question 2 : Henderson Hasselbalch Equation.
Explanation : The Henderson-Hasselbach equation can be used to find the answer. When we plug the given numbers into this equation, we get:. Example Question 3 : Henderson Hasselbalch Equation. Explanation : To find the answer to this question, we must use the Henderson-Hasselbach equation: refers to the concentration of base in this case, ammonium chloride.
Example Question 4 : Henderson Hasselbalch Equation. Explanation : In this question, we're given two different solutions. Example Question 5 : Henderson Hasselbalch Equation. Possible Answers: 3. Correct answer: 4. Improve this answer. Karsten Theis Karsten Theis Yes, but you should still keep in mind some limitations. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown.
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