CHY 122 - Chapter 16: Acid-Base Equilibrium

arrhenius acid

increases [H+] in aqueous solution

arrhenius base

increase [OH-] in aqueous solutions

bronsted acid

acts as a proton donor; must have at least one acidic H+ that can be removed

bronsted base

acts as a proton acceptor; must have at least one non-bonding pair of electrons

conjugate base

formed by removing a proton from the acid

conjugate acid

formed by adding a proton to the base

amphiprotic

a substance capable of acting as both an acid and a base

strong acids

fully dissociate in aqueous solution to give H+; conjugate base has negligible basicity

strong bases

fully dissociate in aqueous solution to give OH-; conjugate acid has negligible acidity

HCL, HBr, HI, HClO3,HClO4, HNO3, H2SO4

strong acids

acid-base equilibria

equilibrium favors transfer of the proton from the stronger acid to the stronger base

autoionization

two molecules of the same compound react together - one molecule acts as the acid, one molecule acts as the base

acidic

[H+]>[OH-]

neutral

[H+]=[OH-]

basic

[H+]<[OH-]

pH

a method of reporting the concentration of [H+]

pOH

a method of reporting the concentration of [OH-]

0-6.99

acidic

7

neutral

7.01 - 14

basic

strong bases

LiOH, NaOH, KOH, RbOH, CsOH, Ca(OH)2, Sr(OH)2, Ba(OH)2

weak acids and bases

partially dissociate in aqueous solution and exist as an equilibrium mixture

percent ionization

the stronger the acid, the higher the percent ionization

polyprotic acids

acids that have more than one acidic proton; H+ are removed stepwise (one at a time)

weak bases

react with water to form a conjugate acid and OH-

first class of weak bases

neutral molecules with a nonbonding pair of electrons

second class of weak bases

anions of weak acids with nonbonding pairs of electrons

H-A bond polarity

the more polar the H-A bond, the stronger the acid

H-A bond strength

the weaker the H-A bond, the stronger the acid

conjugate base stability

the more stable the conjugate base A-, the stronger the acid

binary acids

consist of H and one other element (Ex. HCl, HF, H2O)

binary acids within a group

H-A bond strength is the most important

binary acids within a period

H-A bond polarity is the most important

oxyacids

consist of H, O, and another nonmetal or metalloid (Ex. H3PO4, HClO); acidity determined by number of OXO groups

carboxylic acid

organic acids which contain a carboxyl group (-COOH)

resonance

stabilizes the anion and increases acidity

lewis acid

acts as an electron-pair acceptor (e- deficient)

lewis base

acts as an electron-pair donor (e- rich)