Chapter 15Chapter 15Acids and BasesAcids and Bases

AcidsAcidsVocabulary – Hydrogen ion = HVocabulary – Hydrogen ion = H+1+1 = Proton = ProtonGeneral Properties of Acids:Acids have a sour taste (ex – citrus fruits, soda, vinegar)Many acids contain hydrogen. Some react with active metals to liberate hydrogen gas(Remember Zn + HCl )

Acids change the color of indicatorsAcids react with base to produce salt and water

HCl + NaOH NaCl + H2OAcids are electrolytes

Acid DefinitionsAcid Definitions

An acid may fit one, two An acid may fit one, two or all three definitionsor all three definitions

Traditional definition Traditional definition (Arrhenius) –(Arrhenius) –

Acids contain Hydrogen Acids contain Hydrogen ion(s) and give them ion(s) and give them up when in waterup when in water

HCl (g) ---> H+ (aq) + Cl- (aq)H2O

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VIDEO CLIP!!

Acid DefinitionsAcid DefinitionsAn acid may fit one, two or all three An acid may fit one, two or all three

definitionsdefinitions

Bronsted definition–Bronsted definition–

Acids are proton Acids are proton DONORSDONORS

-Similar to Arrhenius definition, but there -Similar to Arrhenius definition, but there must be another substance for the acid to must be another substance for the acid to give the proton to.give the proton to.

HCl (g) + H2O (l) --> H3O+ (aq) + Cl- (aq)

Acid DefinitionsAcid DefinitionsAn acid may fit one, two or all three An acid may fit one, two or all three

definitionsdefinitionsLewis definition–Lewis definition–Acids are electron pair acceptorsAcids are electron pair acceptors-The acid might not even have a hydrogen in -The acid might not even have a hydrogen in

itit

+

Accepts an e- pair from NH3

StrongStrong Acid: Acid:

-Ionizes nearly 100%-Ionizes nearly 100%

Examples to Examples to memorizememorize::

-HCl (hydrochloric acid)-HCl (hydrochloric acid)

-H-H22SOSO44 (sulfuric acid) when losing the first (sulfuric acid) when losing the first

protonproton

HCl H+ + Cl-

WeakWeak Acid: Acid:

-Ionizes less than 100%-Ionizes less than 100%

-Lots of the unionized acid will remain-Lots of the unionized acid will remain

Examples to memorize:Examples to memorize:

-HF (hydrofluoric acid)-HF (hydrofluoric acid)

-HCH-HCH33COO / CHCOO / CH33COOH (acetic acid)COOH (acetic acid)

HF H+ + F-REMEMBER – STRONG/ WEAK DOES NOT RELATE TO DANGER LEVEL!!

Classifying AcidsClassifying AcidsMonoprotic – 1 proton to loseMonoprotic – 1 proton to lose

ex – HCl (hydrochloric acid)ex – HCl (hydrochloric acid)

Polyprotic – More than 1 proton to losePolyprotic – More than 1 proton to lose

Diprotic – 2 protons to loseDiprotic – 2 protons to lose

ex – Hex – H22SOSO4 4 (sulfuric acid)(sulfuric acid)

Triprotic – 3 protons to loseTriprotic – 3 protons to lose

ex – Hex – H33POPO4 4 (phosphoric acid)(phosphoric acid)

Acid Structure and NamingAcid Structure and Naming

Binary Acids – H and one other atomBinary Acids – H and one other atom

example – HF, HI, HClexample – HF, HI, HCl

Naming – Naming – Hydro --- ic acidHydro --- ic acid

example – example – hydrofluoric acidhydrofluoric acid

hydroiodic acidhydroiodic acid

hydrochloric acidhydrochloric acid

Oxyacids – Have oxygenOxyacids – Have oxygen

-Come from the eight -ates-Come from the eight -ates

ION NAME ACID NAME2 LESS O HYPO – ITE HYPO – OUS ACID1 LESS O ITE OUS ACIDMEMORIZED ATE IC ACID1 MORE O PER – ATE PER – IC ACID

Examples: FROM SULFATE (SO4-2)

H2SO2

H2SO3

H2SO4

H2SO5

Hyposulfurous Acid

Sulfurous Acid

Sulfuric Acid

Persulfuric Acid

**Know the acids from sulfate, nitrate, chlorate, phosphate!!**Know the acids from sulfate, nitrate, chlorate, phosphate!!

Examples – sulfuric, sulfurous, nitric, perchloric, Examples – sulfuric, sulfurous, nitric, perchloric, phosphoric, etc.phosphoric, etc.

*Some Other Common Acids to Know:*Some Other Common Acids to Know:

HydrochloricHydrochloricHydrofluoricHydrofluoricHydroiodicHydroiodicHydrobromicHydrobromicAceticAcetic

BasesBasesGeneral Properties of Bases:-Bases have a bitter taste (soap, bakers choc)

-Dilute aqueous solutions feel slippery (soap)

-Bases change the color of indicators

-Bases react with acids to produce salts and water HCl + NaOH NaCl + H2O

-Bases are electrolytes

Base DefinitionsBase Definitions

A base may fit one, two or all three A base may fit one, two or all three definitionsdefinitions

Traditional definition (Arrhenius) –Traditional definition (Arrhenius) –

A base contains Hydroxide ion(s) and gives A base contains Hydroxide ion(s) and gives them up when in waterthem up when in water

KOH (s) K+ (aq) + OH- (aq)

H2O

Base DefinitionsBase DefinitionsAn acid may fit one, two or all three An acid may fit one, two or all three

definitionsdefinitions

Bronsted definition–Bronsted definition–

Bases are proton ACCEPTORSBases are proton ACCEPTORS

HCl (g) + H2O (l) H3O+ (aq) + Cl- (aq)

BASE

Base DefinitionsBase DefinitionsAn acid may fit one, two or all three An acid may fit one, two or all three

definitionsdefinitions

Lewis definition–Lewis definition–

Bases are electron pair donatorsBases are electron pair donators

+

Donates an e- pair to the BF3

Neutralization ReactionsNeutralization Reactions

Stoichiometry of Acid – Base Neutralization Stoichiometry of Acid – Base Neutralization ReactionsReactions

Acid + Base Acid + Base Water + A Salt Water + A Salt (an ionic compound)(an ionic compound)

Examples:

WeakWeak Base: Base:

-Ionizes less than 100%-Ionizes less than 100%

-Lots of the unionized base will remain-Lots of the unionized base will remain

Example to memorize:Example to memorize:

-NH-NH33 (ammonia) (ammonia)

StrongStrong Base: Base:

-Ionizes almost 100%-Ionizes almost 100%

Examples to memorize:Examples to memorize:

-Group 1 metal hydroxides (NaOH, KOH, etc.)-Group 1 metal hydroxides (NaOH, KOH, etc.)

REMEMBER – STRONG/ WEAK DOES NOT RELATE TO DANGER LEVEL!!

Relative Strength of Acids and Relative Strength of Acids and BasesBases

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

Acid Base

Conjugate – The “leftover” after acid + base combine

Conjugate Base – The left over after an ACID loses its Hydrogen ion (take a H away from the acid!)

Conjugate Base

Conjugate Acid – The left over after a BASE gains its Hydrogen ion (add an H to the base!)

Conjugate Acid

Another Example:

NH3 + H2O NH4+ + OH-

Know:Know:

Strong Acids:Strong Acids:

-Hydrochloric-Hydrochloric

-Sulfuric (1-Sulfuric (1stst H+ only) H+ only)

Weak Acids:Weak Acids:

-Hydrofluoric-Hydrofluoric

-Acetic-Acetic

Relative Strength of Acids and Relative Strength of Acids and BasesBases

Know:Know:

Strong Bases:Strong Bases:

-Metal hydroxides-Metal hydroxides

Weak Bases:Weak Bases:

-Ammonia-Ammonia

**The stronger the acid – the weaker the conjugate base****The stronger the acid – the weaker the conjugate base**

**The stronger the base – the weaker the conjugate acid****The stronger the base – the weaker the conjugate acid**

Relative Strength of Acids and Relative Strength of Acids and BasesBases

Example –

Which is the stronger conjugate base – acetate or chloride??

15.4 – Oxides, Hydroxides, Acids15.4 – Oxides, Hydroxides, Acids

Metal oxide + Water Metal oxide + Water Base Base

Ex – NaEx – Na22O + HO + H22O O 2NaOH 2NaOH

Nonmetal oxide + Water Nonmetal oxide + Water Acid Acid

Ex – SOEx – SO22 + H + H22O O H H22SOSO33

SOSO33 + H + H22O O H H22SOSO44

Reactions of Acids and BasesReactions of Acids and Bases

1.1. Acids react with many metals to form Acids react with many metals to form Hydrogen gasHydrogen gas

2.2. Acids react with metal oxidesAcids react with metal oxides

3.3. Acids react with carbonates to form Acids react with carbonates to form carbon dioxide gascarbon dioxide gas

4.4. Hydroxides react with nonmetal oxidesHydroxides react with nonmetal oxides

5.5. Metal oxides react with nonmetal oxidesMetal oxides react with nonmetal oxides