Salts

Salt Solutions•The salts of weak acids

can recombine with water producing basic

solutions

Salt Solutions•The salts of weak bases

can recombine with water producing acidic

solutions

Salt Solutions A- + H2O HA + OH-

B+ + H2O H+ + BOH

Salt or Hydrolysis Problems

Salt Problem• Calculate the pH of a

0.20 M solution of NaBz

• Ka = 6.4 x 10-5

Salt Problem• Calculate the pH of a 0.10 M solution of R-

NH3Cl

• Kb = 2.5 x 10-5

Salt Applications

•Salts of strong acids & weak bases make

acidic solutions

Salt Applications

•Salts of strong bases & weak acids make

basic solutions

Salt Applications

•Salts of strong acids & strong bases make

neutral solutions

Predict Relative pH

•NaAc BaCl2

•KNO3 NH4Br

•KHSO4 NH4Ac

Predict Relative pH

•KAcNaCl•KClO2 NH4Cl

•K2SO4 NaI

Anhydrides•Compounds without

water; that when added to water, form

other compounds

Acid Anhydrides

•Non-metal oxides that form acids when

added to water

Basic Anhydrides•Metal oxides that form bases when added to water

Predict Relative pH•Na2O SO2

•NO2CO2

•CaO Al2O3

Buffer & Salt Hydrolysis Problems

Calculate the pH of 1.0 M HF in 0.50 M NaF.

Ka HF = 6.5 x 10-4

Calculate the pH of 5.0 M KCN.

KaHCN= 5.0 x 10-10

Calculate [H3PO4], [H2PO4-1],

[HPO4-2], [PO4

-3], [K+], [H+], & pH of 1.0 M KH2PO4 in

0.50 M K2HPO4. Ka1 = 7.5 x 10-3

Ka2 = 6.2 x 10-8

Ka3 = 4.2 x 10-13

Calculate pH of:0.50 M MOH in

0.20 M MClKb = 5.0 x 10-5

Calculate pH of:0.20 M MCl

Kb = 5.0 x 10-5

Review of Acid/Base descriptions and

Acid/Base, Buffer, & Salt Equilibria

Arhenius, Bronsted-Lowry, & Lewis Acids & Bases

Strong Acids

Strong Bases

Acid rxns

Base rxns

A/B Equilibrium Constants

KW, KA, KB, & pH

Calculate pH of:•0.025 M HNO3

•0.020 M KOH

Calculate pH of:•2.0 M HNO2

•Ka = 2.0 x 10-4

Calculate pH of:•3.0 M HZ in

2.0 M KZ•Ka HZ = 3.0 x 10-5

Calculate pH of:•0.20 M KQ•Ka HQ = 2.0 x 10-5

150 mL of 0.10 M KOH was added to 100.0 mL of 0.10 M H2CO3. Calculate [H2CO3],

[HCO3-], [CO3

-2], [H+], [OH-], & pH of the solution.

Ka1 = 4.4 x 10-7

Ka2 = 4.7 x 10-11

Calculate [H3A], [H2A-1], [HA-2], [A-3], [K+], [H+],

[OH-], & pH of 2.0 M KH2A. Ka1 = 4.0 x 10-3

Ka2 = 5.0 x 10-8

Ka3 = 2.5 x 10-13

Calculate pH of:•2.0 M HQ•Ka = 2.0 x 10-6

Calculate pH of:•6.0 M HZ in

4.0 M KZ•Ka HZ = 3.0 x 10-5

Calculate pH of:•0.20 M KQ•Ka HQ = 2.0 x 10-7