2010-03-01 - Polyprotic Acids and Bases & Autoprotolysis and pH

2010-03-01 - Polyprotic Acids and Bases & Autoprotolysis and pH

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
PROPERTIES OF SOLUTIONS: Ch 7 – Acids and Bases References: - Chemical Principles, Steven S. Zumdahl, Fifth Edition, Houghton Mifflin Custom Publishing, Boston, MA - Professor Paul Mc Cord Notes, CH 302, University of Texas at Austin 1 Polyprotic Acids and Bases & Autoprotolysis and pH
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Very Dilute Solutions of Strong Acids and Bases - We have to include the contribution of autoprotolysis when the concentration of the strong acid or base is < 10 -6 M 1 - Charge balance [H 3 O + ]=[Cl - ] + [OH - ] 2 - Material balance [Cl - ]=[HCl] initial 3 - Autoprotolysis K w =[H 3 O + ][OH - ] In very dilute solutions of strong acids and bases, the pH os significantly affected by the autoprotolysis of water Very Dilute Solutions of Weak Acids - Autoprotolysis also contribute to the pH of very dilute solutions of weak acids 1 - Charge balance [H 3 O + ]=[A - ] + [OH - ] 2 - Material balance [HA] initial = [HA] + [A-] 3 - Autoprotolysis K w =[H 3 O + ][OH - ] 4 – Acidity Constants K a =[H 3 O + ][A - ]/[HA] ] [ ] [ ] [ ] [ ] [ ] [ 3 3 3 3 3 O H k O H HA O H k O H O H K w initial w a
Background image of page 2
If pH < 6
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 4
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: ] [ ] [ ] ][ [ 3 3 3 O H HA O H O H K initial a If 6 < pH < 7, solve cubic equation ) ] [ ( 2 3 w a initial a w a K K x HA K K x K x In aqueous solutions of very weak acids, the autoprotolysis of water must be taken into account if the H + concentration is < 10-6 M The pH of a Polyprotic Acid Solution-A polyprotic acid is a compound that can donate more than one proton-A polyprotic base is a species that can accept more than one proton Estimate the pH of a polyprotic acid by using only the first deprotonation equilibrium and assuming that further deprotonation is insignificant (exception is sulfuric acid) Solutions of Salts of Polyprotic Acids 2 1 2 1 a a pK pK pH The pH of an amphiprotic salt is equal to the average of the pKas of the salt and its conjugate acid-Calculate the concentration of all species in 0.10 M H 3 PO 4(aq) Composition and pH...
View Full Document

This note was uploaded on 03/01/2011 for the course CH 302 taught by Professor Holcombe during the Spring '07 term at University of Texas at Austin.

Page1 / 4

2010-03-01 - Polyprotic Acids and Bases & Autoprotolysis and pH

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online