ACIDS & BASESACIDS & BASES

Acid Nomenclature Acid Nomenclature FlowchartFlowchart

h yd ro - p re fix-ic en d in g

2 e lem en ts

-a te en d in gb ecom es-ic en d in g

-ite en d in gb ecom es

-o u s en d in g

n o h yd ro - p re fix

3 e lem en ts

AC ID Ss ta rt w ith 'H '

Binary

-ide

Oxyacids or Ternary

-ite

-ate

NAMES AND FORMULASA Review

HX means HX means AcidAcid

If anion ends in If anion ends in “–ide”“–ide”

Acid name begins withAcid name begins with “hydro-”“hydro-”

Ends with Ends with “–ic“–ic”” , followed by , followed by “Acid”

HCl – HCl – HydroHydrochlorchloricic Acid (Chloride)Acid (Chloride)

HBr – HBr – HydroHydrobrombromicic Acid (Bromide)Acid (Bromide)

HCN – HCN – HydroHydrocyancyanic Acid (Cyanide)ic Acid (Cyanide)

NAMES AND FORMULAS

If anion ends in If anion ends in “–ite”“–ite”

Acid ends with Acid ends with “–ous”,“–ous”, followed by followed by “Acid”“Acid”

HH22SOSO33 – Sulfur – Sulfurousous AcidAcid

HNOHNO22 – Nitr – Nitrousous AcidAcid

HH33POPO33 – Phosphor – Phosphorousous AcidAcid

NAMES AND FORMULAS

If anion ends in “–ate“–ate””

Acid ends with “–ic“–ic”” ,followed by “Acid”“Acid”

H2SO4 – Sulfuric Acid

HNO3 – Nitric Acid

H3PO4 – Phosphoric Acid

NAMES AND FORMULAS

Bases Bases named same as ionic compound

NaOH –Sodium HydroxideHydroxide (Lye)Ca(OH)2 – Calcium HydroxideHydroxide (Lime)

Pb(OH)2 – Lead Hydroxide Hydroxide

KOH – Potassium HydroxideHydroxide

WATER IONIZATIONWATER IONIZATION

Water molecules in continuous random motion

Collisions between two molecules

Result in transfer of hydrogen ion

H2O + H2O HH33OO++ + OHOH--

HH33OO++ = hydronium ion

OHOH-- = hydroxide ion

3 Theories3 TheoriesAcid-Base TheoriesAcid-Base Theories

3 Theories Acid/Base3 Theories Acid/Base

Theory #1: Arrhenius (traditional) Theory #1: Arrhenius (traditional)

a) a) Acids – Acids – produce Hproduce H++ ions (or ions (or hydronium ions Hhydronium ions H33OO++) in aqueous solution) in aqueous solution

b) b) BasesBases – – produces OHproduces OH-- ions in aqueous ions in aqueous solutionssolutions

i: Monoprotic Acid gives up 1 H+ (HCL)

ii: Diprotic Acid gives up 2 H+ (H2SO4)

iii: Triprotic Acid gives up 3 H+ (H3PO4)

Arrhenius acid is a substance that produces H+ (H3O+) in water

Arrhenius base is a substance that produces OH- in water

Brønsted – LowryBrønsted – Lowry Theory #2: Brønsted – Lowry

a) Acids – proton (H+) donora) Acids – proton (H+) donor (H+ is given away)(H+ is given away)

b) Bases – proton (H+) acceptorb) Bases – proton (H+) acceptor (H+ gained)(H+ gained)

A A “proton“proton” is really just a ” is really just a hydrogen atom that has lost it’s hydrogen atom that has lost it’s electron!electron!

A Brønsted-Lowry acid is a proton donorA Brønsted-Lowry base is a proton acceptor

acid conjugate

basebase conjugate

acid

LewisLewis

a)a) Lewis acid –Lewis acid – electron pair electron pair acceptoracceptor

b) Lewis base –b) Lewis base – electron pair donorelectron pair donor

Theory #3 – Lewis Theory #3 – Lewis

WATER DISSOCIATION,SIMPLIFIED

Dissociation of water:

H2O H+ + OH-

One H+ and one OH- produced, so

[H+] = [OH-]

[ X ] = concentration (Molarity)

PROPERTIES OF ACIDS• Sour or tart taste in foodsSour or tart taste in foods

• Strong Acid = Strong Strong Acid = Strong ElectrolyteElectrolyte

• Release Release H+H+ ions in water ions in water

• Turn blue litmus paper RedTurn blue litmus paper Red

Hydrogen Ion in WaterHydrogen Ion in Water

Water + a proton Hydronium Ion

H2O + H+ H3O +1

The H+ ion has no electrons so it attached itself to a water molecule to share its electrons

ARRHENEIUS ACIDSARRHENEIUS ACIDS

Theory developed by Arrhenius (1859-1927)rrhenius (1859-1927)

Defined acids and bases as compounds that ionize to produce HDefined acids and bases as compounds that ionize to produce H++ and and OHOH--

HCl + H2O (1) H3O+ (aq) + Cl - (aq) monoprotic

  H2SO4 + H2O (2) H3O

+ (aq) + SO4-2 (aq)

diprotic  H3PO4 + H2O - (3) H3O

+ (aq) + PO4-3 (aq)

triprotic 

ARRHENIUS ARRHENIUS ACIDSACIDS Theory: substance that contains hydrogen,

and releases the H+ in water

Types of Arrhenius AcidsTypes of Arrhenius Acids

Triprotic acids contain 3 ionizable protons

H3PO4

Monoprotic acids contain 1 ionizable proton HCl, HBr, HF, HI

Diprotic acids contain 2 ionizable protons

H2SO4

PROPERTIES OF BASES• Feels slipperyFeels slippery• Bitter tasteBitter taste• Strong Base = Strong ElectrolyteStrong Base = Strong Electrolyte• Produce Produce hydroxide ionshydroxide ions in water in water• Red litmus turns Blue in a Base Red litmus turns Blue in a Base

(RBB)(RBB)

EX: LYE USED IN SOAPMAKINGEX: LYE USED IN SOAPMAKING AMMONIA USED IN CLEANINGAMMONIA USED IN CLEANING

ARRHENIUS BASESARRHENIUS BASESSubstance that contains OH and

releases the OH-OH- in water.

NaOH + H2O Na+1 (aq) + OHOH-- (aq)

Mg(OH)2 + H2O Mg +2 (aq) + 2 OHOH--

(aq)

Some DefinitionsSome Definitions Arrhenius acids and basesArrhenius acids and bases

Acid:Acid: Substance that, when Substance that, when dissolved in water, increases the dissolved in water, increases the concentration of hydrogen ions concentration of hydrogen ions (protons, H(protons, H++).).

Base:Base: Substance that, when Substance that, when dissolved in water, increases the dissolved in water, increases the concentration of hydroxide ions.concentration of hydroxide ions.

Complete book practice problemsComplete book practice problems Pg 609Pg 609 #34,43,44,45,46#34,43,44,45,46 Or check your Power packet ( Acids Or check your Power packet ( Acids

+ Bases) pg 9+ Bases) pg 9

WhoWhoTheory:Theory:

Acid=Acid=WhenWhen

ArrheniusArrhenius increases increases HH++ 1880’s1880’s

Brønsted & Brønsted & LowryLowry

proton proton donordonor 19231923

LewisLewisElectron-Electron-pair pair acceptoracceptor

19231923

Three definitions of acid

ALTERNATE THEORIESALTERNATE THEORIESNot all materials with acidic/basic properties

in aqueous solution contain H or OH.

Don’t fit Arrhenius definition of acids & base

Thomas Lowry (1874-1936) independently proposed a new definition.

Johannes Brønsted (1879-1947) and

Some DefinitionsSome Definitions BrønstedBrønsted––Lowry: must have Lowry: must have bothboth

1. an Acid:1. an Acid: Proton donorProton donor

andand

2. a Base:2. a Base: Proton acceptorProton acceptor

BrBrøønsted – Lowry Acids and Basesnsted – Lowry Acids and Bases

B/L Acid is a hydrogen ion donor

B/L base is a hydrogen ion acceptor

Arrhenius acids and bases fit into the Brønsted – Lowry Theory

The Brønsted-Lowry acid donates a proton,

while the Brønsted-Lowry base accepts it.

Brønsted-Lowry acids and bases are always paired.

Which is the acid and which is the base in each of these rxns?

BrBrøønsted – Lowry Acids and Bases nsted – Lowry Acids and Bases

NH3 + H2O NH4+ + OH-

Ammonia is a base accepts hydrogen ion

Water is an acid donates hydrogen ion

What Happens When an Acid What Happens When an Acid Dissolves in Water?Dissolves in Water?

Water acts as a Water acts as a BrønstedBrønsted––Lowry base Lowry base and abstracts a and abstracts a proton (Hproton (H++) from the ) from the acid.acid.

As a result, the As a result, the conjugate baseconjugate base of of the acid and a the acid and a hydronium ionhydronium ion are are formed.formed.Movies…

A BrønstedA Brønsted––Lowry acid…Lowry acid…

……must have a removable (acidic) proton.must have a removable (acidic) proton.

HCl, HHCl, H22O, HO, H22SOSO44

A BrønstedA Brønsted––Lowry base…Lowry base…

……must have a pair of nonbonding must have a pair of nonbonding electrons.electrons.

NHNH33, H, H22OO

Conjugate Acids and Bases:Conjugate Acids and Bases: From the Latin word From the Latin word conjugareconjugare, meaning , meaning

“to join together.”“to join together.” Reactions between Reactions between acidsacids and and basesbases always always

yield their yield their conjugate basesconjugate bases and and acids.acids.

BrBrøønsted – Lowry Acids and Bases nsted – Lowry Acids and Bases

Conjugate Acid Conjugate Acid

Formed when a base gains a hydrogen ion.

NH4+ is the Conjugate Acid

Conjugate BaseConjugate Base

What remains when an acid has donated the hydrogen ion.

OH- is the Conjugate Base

BrBrøønsted – Lowry Acids and Basesnsted – Lowry Acids and Bases

)()()()( 423 aqOHaqNHlOHaqNH

Base

Acid Conjugate Acid

Conjugate Base

Conjugate acid / base pair

Brønsted – Lowry Acids and Bases Brønsted – Lowry Acids and Bases

Two substances that are related by the loss or gain of a hydrogen ion.

Water is Amphoteric - Acts as both Acid and Base

HCl + HHCl + H22O O H H33OO++ + Cl + Cl--

In General:Conjugate Base of a Strong Acid is weak

HCl (acid) has a weak conjugate base in Cl-

Brønsted – Lowry Acids and Bases Brønsted – Lowry Acids and Bases

Conjugate Acid of a Strong Base is weakNaOH (base) has a weak conjugate acid in Na+

ALTERNATE THEORIESALTERNATE THEORIESGilbert Lewis (1875-1946) focused

on the donation or acceptance of electrons.

Remember the Lewis Dot Structure?This is the same guy…

Lewis acid acceptsaccepts electrons to form a covalent bondLewis base donatesdonates electrons to form a covalent bond

Acid-Base DefinitionsAcid-Base Definitions

TypeType AcidAcid BaseBase

ArrheniusArrhenius HH++ producer producer OHOH-- producer producer

BrBrønsted-ønsted-LowryLowry

HH++ donor donor HH++ acceptor acceptor

LewisLewis Electron-pair Electron-pair acceptoracceptor

Electron-pair Electron-pair donordonor