1 / 14

Acid-Base Titrations

Acid-Base Titrations. Acid-Base Titrations. Add solution (either the acid or the base) from buret to solution in flask The concentration of one solution is known. One concentration is unknown.

ceana
Download Presentation

Acid-Base Titrations

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Acid-Base Titrations

  2. Acid-Base Titrations • Add solution (either the acid or the base) from buret to solution in flask • The concentration of one solution is known. One concentration is unknown. • The goal is to find the equivalence point: the point at which stoichiometrically equivalent quantities of acid and base have been combined (moles of acid = moles of base).

  3. Acid-Base Titrations Can use an indicator to signal the equivalence point. An indicator is a dye that changes colors within a certain pH range. End point – point of indicator color change

  4. Acid-Base Indicators

  5. Acid-Base Indicators Can use an indicator to signal the equivalence point. An indicator is a dye that changes colors within a certain pH range. End point – point of indicator color change Must select an indicator with an end point approx. equal to the equivalence point of the acid-base reaction

  6. Acid-Base Indicators • Usually a weak acid. Can be a weak base. • Shows distinctly different colors in non-ionized and ionized forms: HIn H+ + In- acid form base form

  7. Acid-Base Indicators HIn H+ + In- acid form base form In acid: H+ concentration high equilibrium shift to left color of HIn In base: OH- consumed H+ equilibrium shifts to right color of In-

  8. Acid-Base Titrations Can use pH meter and plot a titration curve. The equivalence point is the most vertical part of the curve.

  9. Generic Titration Curve

  10. Acid-Base Titrations We will look at three kinds of titrations: • Strong acid by a strong base • Weak acid by a strong base • Weak base with a strong acid

  11. Acid-Base Titrations For each type, we will learn to write reactions for and calculate pH at four different points in the titration: • The initial pH before any titrant is added • At any point between the initial pH and the equivalence point • At the equivalence point • After the equivalence point

  12. Strong Acid – Strong Base Titration • Describe a strong acid in solution. • What happens between a strong acid and a strong base? • At the equivalence point, what is true? • What happens after that? (What do you have present in solution after that?)

  13. Weak Acid – Strong Base Titration • Describe a weak acid in solution. • What happens between a weak acid and a strong base? • At the equivalence point, what is true? • What happens after that? (What do you have present in solution after that?)

  14. Weak Base – Strong Acid Titration • Describe a weak base in solution. • What happens between a weak base and a strong acid? • At the equivalence point, what is true? • What happens after that? (What do you have present in solution after that?)

More Related