1 / 7

BUFFERS

this a presentation about buffers

gonnach
Télécharger la présentation

BUFFERS

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. ISM99 BUFFERS

  2. DEFINATION: • A buffer is an aqueous solution consisting of a mixture ofa weak acid and its conjugate base or a weak base and itsconjugate acid. • Its pH changes very little when a small amountof strong acid or base is added to it • It is used to prevent changes in the pH of a solution.

  3. Weak Acid And Conjugate Base: • Weak acids have only a modest tendency to shed theirprotons (definition of an acid). • • When they do, the corresponding negatively chargedanion becomes a willing proton acceptor, and is called theconjugate base

  4. Acid dissociation constant(pKa) • An acid dissociation constant, pKa, (also knownas acidity constant, or acid-ionization constant) isa quantitative measure of the strength of an acid insolution. It is the equilibrium constant for a chemicalreaction known as dissociation in the context of acid base reactions.

  5. How it works? • A buffer is a solution of a weak acid and its conjugate base thatresists changes in pH in both directions—either up or down.• A buffer works best in the middle of its range, where the amountof dissociated acid is about equal to the amount of the conjugatebase.• One can soak up excess protons (acid), the other can soak upexcess hydroxide (base).

  6. pH Curve:

  7. Thank you??????

More Related