Arrhenius Acids & BasesArrhenius Acids & Bases

ACIDSACIDS– Monoprotic (HNOMonoprotic (HNO33))– Diprotic (HDiprotic (H22SOSO44))– Triprotic (HTriprotic (H33POPO44))

– Yield Hydrogen ions Yield Hydrogen ions (H+) in aqueous (H+) in aqueous solutionsolution

BASESBASES– Forms Hydroxide Forms Hydroxide

ions (OH-) in ions (OH-) in aqueous solutionaqueous solution

BRONSTED – LOWERY BRONSTED – LOWERY ACIDSACIDS

ACIDSACIDS– Donates a Donates a

proton/hydrogen proton/hydrogen ionion

BASESBASES– Accept Accept

proton/hydrogen proton/hydrogen ionion

AcidsAcids

Tart/sour tasteTart/sour taste Acid solutions are electrolytes Acid solutions are electrolytes

(conduct electricity)(conduct electricity) Cause indicators to change colorCause indicators to change color High concentrations of hydrogen ionsHigh concentrations of hydrogen ions [H+][H+] pH 0 – 6.9pH 0 – 6.9

BasesBases

Bitter tasteBitter taste Slippery feelSlippery feel Aqueous solutions are electrolytesAqueous solutions are electrolytes Cause an indicator to change colorCause an indicator to change color High hydroxide ion concentrationHigh hydroxide ion concentration [OH-][OH-] pH 7.1 – 14.0pH 7.1 – 14.0

What ions do acids produce in greater concentrations in a solution?

What ions do bases produce in greater concentrations in a solution?

CONCENTRATED VS. DILUTECONCENTRATED VS. DILUTE

STRONG ACIDSSTRONG ACIDS HFHF HClHCl HBrHBr HIHI HNOHNO33

HH22SOSO44

“STRONG” indicates the degree of dissociation!!!

NOT the degree of concentration!!!

WEAK ACIDSWEAK ACIDS

Acids that DO NOT 100% dissociate Acids that DO NOT 100% dissociate REMINDERS:REMINDERS:

– Acids of VERY high concentrations Acids of VERY high concentrations (greater than 1M), will not 100% (greater than 1M), will not 100% dissociate dissociate

– ALL acids have SOME concentration of ALL acids have SOME concentration of hydroxide ions….WHY??hydroxide ions….WHY??

STRONG BASESSTRONG BASES

GROUP I HYDROXIDESGROUP I HYDROXIDES

LiOH - lithium hydroxide LiOH - lithium hydroxide NaOH - sodium hydroxide NaOH - sodium hydroxide KOH - potassium hydroxide KOH - potassium hydroxide RbOH - rubidium hydroxide RbOH - rubidium hydroxide CsOH - cesium hydroxideCsOH - cesium hydroxide

STRONG BASESSTRONG BASES

GROUP II HYDROXIDESGROUP II HYDROXIDES

*Ca(OH)*Ca(OH)22 - calcium hydroxide - calcium hydroxide

*Sr(OH)*Sr(OH)22 - strontium hydroxide - strontium hydroxide

*Ba(OH)*Ba(OH)22 - barium hydroxide - barium hydroxide

* These bases completely dissociate in solutions of * These bases completely dissociate in solutions of 0.01 M 0.01 M or lessor less. The other bases make solutions of 1.0 M and are . The other bases make solutions of 1.0 M and are 100% dissociated at that concentration. There are other 100% dissociated at that concentration. There are other strong bases than those listed, but they are not often strong bases than those listed, but they are not often encountered.encountered.

WEAK BASESWEAK BASES

Bases that DO NOT 100% completely Bases that DO NOT 100% completely dissociatedissociate

REMINDERS:REMINDERS:– Bases of VERY high concentrations Bases of VERY high concentrations

(greater than 1M), will not 100% (greater than 1M), will not 100% dissociate dissociate

– ALL bases have SOME concentration of ALL bases have SOME concentration of hydrogen ions….WHY??hydrogen ions….WHY??

Ionization ConstantIonization ConstantExample:Example:

Ammonia in waterAmmonia in water

Ionization ConstantIonization ConstantExample:Example:

Ionization of nitric acidIonization of nitric acid

Ionization Constants: KIonization Constants: Kaa, , KKbb, and K, and Kww

• Ka

• Kb

• Kw

http://www.saskschools.ca/curr_content/chem30_05/5_acids_bases/acids2_2.htm

Ionization Constants: KIonization Constants: Kaa, , KKbb, and K, and Kww

A large value of KA large value of Kaa means there are many means there are many HH++ ions in solution - ions in solution -in other words, in other words, a strong acida strong acid

A large KA large Kbb indicates indicates many OHmany OH-- ions - ions -a strong basea strong base

Practice SetPractice Set

Calculating pH/pOHCalculating pH/pOH

[H[H++] = 10] = 10-pH-pH

[OH[OH--] = 10] = 10-pOH-pOH

[H[H++] [OH] [OH--] = 1 x 10] = 1 x 10-14-14

pH = -log [HpH = -log [H++]] pOH = -log pOH = -log

[OH[OH--]]

pH + pOH = 14pH + pOH = 14

Warm-UpWarm-UpA 25.00 mL sample of a 0.5250 A 25.00 mL sample of a 0.5250 M HM H22SOSO4 4 solution is titrated with solution is titrated with

a NaOH solution using a NaOH solution using phenolphthalein as the phenolphthalein as the

indicator. It is found that 22.07 indicator. It is found that 22.07 mL of the NaOH solution is mL of the NaOH solution is

needed to reach the endpoint of needed to reach the endpoint of the titration. What is the the titration. What is the

molarity of the NaOH solution?molarity of the NaOH solution?