Acids & Bases

Text book• Section 8.2A• Sections 16.1 & 16.2

Self-ionization of water

(Autoionization)

TruthH2O + H2O H3O+ + OH-

Convenient LieH2O H+ + OH-

H3O+ = hydronium ion

H+ = hydrogen ion

OH- = hydroxide ion

ACID BASE

Taste

Slippery?

Litmus

Phenol-phthalein

ACID BASE

Taste Sour Bitter

Slippery?

Litmus

Phenol-phthalein

ACID BASE

Taste Sour Bitter

Slippery? No Yes

Litmus

Phenol-phthalein

ACID BASE

Taste Sour Bitter

Slippery? No Yes

Litmus Red Blue

Phenol-phthalein

ACID BASE

Taste Sour Bitter

Slippery? No Yes

Litmus Red Blue

Phenol-phthalein

Colorless Red

acid

base

PHENOLPHTHALEIN

Page 583

Acids react with active metals to produce hydrogen gas.

(Page 264)

M + HA MA + H2

Example: Zn + 2 HCl ZnCl2 + H2

(A single replacement reaction)

Salt

cation plus the anion of an acid

Acids react with active metals to produce

hydrogen gas.M + HA MA + H2

Example: Zn + 2 HCl ZnCl2 + H2

Ionic: Zn + 2H+ Zn2+ + H2

Acids react with carbonates and

hydrogen carbonates to produce

carbon dioxide and water. (Page 264)

HA + MCO3 MA +CO2 + H2O

Example:2 HCl + CaCO3 CaCl2 + CO2 + H2O

What’s really happening?

2 HCl + CaCO3 CaCl2 + H2CO3

A double replacement reaction.

BUT H2CO3 isn’t stable at room temperature and pressure. It spontaneously decomposes:

H2CO3 H2O + CO2

So…… 2 HCl + CaCO3 CaCl2 + CO2 + H20

Ionic: 2 H+ + CaCO3

Ca2+ + CO2 + H20

HA + MHCO3 MA + CO2 + H2O

EX: HC2H3O2 + NaHCO3 NaC2H3O2 + CO2 + H2O Ionic: HC2H3O2

+ HCO3-

C2H3O2- + CO2 + H2O

HomeworkPredict the products and write complete

balanced reactions.1) Mg(s) + HBr(aq) → 2) Al(s) + HNO3(aq) →3) H2SO4(aq) + K2CO3(aq) →4) MgCO3(s) + HClO4(aq) →

ACID BASE

ArrheniusMake H+

ion in water

Make OH-

ion in water

[H3O+] to [OH-]

Bronsted

ACID BASE

ArrheniusMake H+

Ion in water

Make OH-

Ion in water

[H3O+] to [OH-]

[H3O+] > [OH-] [H3O+] < [OH-]

Bronsted

ACID BASE

ArrheniusMake H+

Ion in water

Make OH-

Ion in water

[H3O+] to [OH-]

[H3O+] > [OH-] [H3O+] < [OH-]

Bronsted proton (H+) donor

proton(H+) acceptor

Definitions• monoprotic – can donate one

proton (HA, EX: HCl)• diprotic – can donate two

protons (H2A, EX: H2SO4)• triprotic – can donate three

protons (H3A, EX: H3PO4)• polyprotic – diprotic and triprotic

Electrolyte formation: AcidsTruth

HA + H2O H3O+ + A-

Convenient LieHA H+ + A-

Ionization

Electrolyte formation: AcidsSee page 563

TruthHCl + H2O → H3O+ + Cl-

Convenient LieHCl → H+ + Cl-

Ionization

Acid Strength• Strong acids ionize completely. • Weak acids do not ionize

completely.• See solubility rules for list of

strong acids.• Figure 16.1 on page 567

Electrolyte formation: BaseCation(OH) Cation+ + OH-

Ex: Ca(OH)2 Ca2+ + 2 OH- (dissociation)

Electrolyte formation: BaseCation(OH) Cation+ + OH-

Ex: Ca(OH)2 Ca2+ + 2 OH- (dissociation)

B + H2O BH+ + OH-

(B = base, BH+ = protonated base)Ex: NH3 + H2O NH4

+ + OH-

(ionization)

Base Strength• Strong bases are hydroxide compounds

that dissociate completely.• See solubility rules for a list of strong

bases.• Weak bases are other hydroxide

compounds (they don’t dissolve significantly into cations and hydroxide) AND all molecular bases (EX: NH3)

Concentration -v- Strength• These two concepts have

nothing to do with each other.• An acid/base can be dilute and

strong (Ex: 0.01M HCl)• An acid/base can be

concentrated and weak (Ex: 8M H2SO3)

Homework• Page 273, #20 (Truth and

convenient lie)• Page 273, #21

Arrhenius neutralization: acid + base water + salt

HBr + NaOH H2O + NaBr

Ionic: H+ + OH- H2O

Homework• Page 273, #22 & 23

BronstedNeutralizationacid + base protonated base + anion

HA + B BH+ + A-

BronstedNeutralizationHA + B BH+ + A-

HCl + NH3 NH4+ + Cl-

Ionic: H+ + NH3 NH4+

Bronsted conjugates(Page 563)

• Acid: HA Conjugate base: A-

• Base: B Conjugate acid: HB+

So……An acid loses proton to become a conjugate base (ready to accept a proton)

And…..A base gains a proton to become a conjugate acid (ready to lose a proton)

Acid-base reaction•One substance donates a proton

•One substance accepts a proton

Page 564• Example 16.1 & 16.2• Practice 16.2• Homework: Page 572,

Section Review #1-5

Relative strength• See page 567.• Strong acid weak conjugate base• Weak acid strong conjugate base• Strong base weak conjugate acid• Weak base strong conjugate acid

Homework• Page 589, #13-16

Water can accept or donate a proton

(Recall autoionization.)

amphoteric or amphiprotic

Examples:

HCl + H2O H3O+ + Cl-

NH3 + H2ONH4+ + OH-

HCl + H2O H3O+ + Cl-

acid base ca cb

NH3 + H2ONH4+ + OH-

base acid ca cb

Lewis definition•Acid = electron pair acceptor

•Base = electron pair donor

coordinate bonding• One atom donates both of

the electrons in the covalent bond

• A coordination complex is formed.

coordinate bonding → coordination complex