Acids and Bases

Chapter 14 – One step closer to the AP Test

Arrhenius DefinitionArrhenius Definition

Acids produce hydrogen ions in aqueous solution.Acids produce hydrogen ions in aqueous solution.

Bases produce hydroxide ions when dissolved in Bases produce hydroxide ions when dissolved in water.water.

Limits to aqueous solutions.Limits to aqueous solutions.

Only one kind of base.Only one kind of base.

NHNH33 ammonia could not be an Arrhenius base. ammonia could not be an Arrhenius base.

Bronsted-Lowry Bronsted-Lowry DefinitionsDefinitions

And acid is an proton (HAnd acid is an proton (H++) donor and a base ) donor and a base is a proton acceptor.is a proton acceptor.

Acids and bases always come in pairs.Acids and bases always come in pairs. HCl is an acid.HCl is an acid. When it dissolves in water it gives its proton When it dissolves in water it gives its proton

to water.to water. HCl(g) HCl(g) HH++ + Cl + Cl--

Water is a base -makes hydronium ionWater is a base -makes hydronium ion

What do all of these have in common?

NH3 H2O CO32-

Dissociate the Following1. Hydrochloric acid

2. Acetic acid

3. Ammonium ion

4. Anilinium ion (C6H5NH3+)

5. Hydrate Aluminum (III) ion [Al(H2O)6]3+

1. HCl H+ + Cl-

2. HC2H3O2 H+ + C2H3O2-

3. NH4+ H+ + NH3

4. C6H5NH3+ H+ + C6H5NH2

5. [Al(H2O)6]3+ H+ + Al(H2O)5OH2+

Polyprotic Acid

Be careful dissociating polyprotic acids. H2SO4 H+ + HSO4

- SA

HSO4- H+ + SO4

2- WA

H3PO4 H+ + H2PO4-

WA

PairsPairs General equation General equation HA(aq) + HHA(aq) + H22O(l) O(l) H H33OO++(aq) + A(aq) + A--(aq)(aq) Acid + Base Acid + Base Conjugate acid +Conjugate acid +

Conjugate base Conjugate base This is an equilibrium.This is an equilibrium. CompetitionCompetition forfor H H++ betweenbetween H H22O and AO and A--

The stronger base controls direction.The stronger base controls direction. If HIf H22O is a stronger base it takes the HO is a stronger base it takes the H++ Equilibrium moves to right.Equilibrium moves to right.

Writing Net Ionic A-B Reactions

1- Determine if the species are an acid, base or salt

2 – Determine if the acid or base are strong or weak

If SA or SB dissociate completely (Show with an )

If WA or WB it reaches equilibrium (Show with an )

3. If a salt, determine if either ion is reactive (Comes from a WA or WB)

Determine whether the reactive ion acts as an acid or base (What type of solution is it in)

Write the reaction of the ion.

4. Write the neutralizations reaction

5. Cross out SA, SB and Salt reactions

6. Add the remaining reactions together

Let’s try one together

Equimolar amounts of hydrochloric acid and potassium hydroxide are mixed.

HCl H+ + Cl- SA

KOH K+ + OH- SB

H+ + OH- H2O

H+ + OH- H2O

Another example0.1M nitrous acid solution is added to the same

volume of a 0.1M sodium hydroxide solution.

(Equimolar amounts = H2O MUST be a product)

HNO2 H+ + NO2- wa

NaOH Na+ + OH- sb

H+ + OH- H2O

HNO2 + OH- H2O + NO2-

Example #2 A solution of potassium hydroxide is added to a

solution of ammonium chloride.KOH K+ + OH- SB

NH4Cl NH4+ + Cl- salt

NH4+ NH3 + H+

H+ + OH- H2O

NH4+ + OH- NH3 + H2O

Example #3Dilute acetic acid solution is added to solid

magnesium carbonate.

HC2H3O2 H+ + C2H3O2- wa

MgCO3 Mg2+ + CO32- salt

CO32- + H2O HCO3

- + OH-

H+ + OH- H2O

HC2H3O2 + CO32- HCO3

- + C2H3O2-

And yet another one…from the WS

Solutions of ammonia and hydrofluoric acid are mixed.

NH3 + H2O NH4+ + OH- wb

HF H+ + F- wa

H+ + OH- H2O

NH3 + HF NH4+ + F-

Problem #2Hydrogen sulfide has is bubbled through a solution of

potassium hydroxide.

H2S H+ + HS- wa

KOH K+ + OH- sb

H+ + OH- H2O

H2S + OH- H2O + HS-

Problem #3 – A twistA solution of sulfuric acid is added to a solution of

barium hydroxide until the same number of moles of each compound has been added.

H2SO4 H+ + HSO4- sa

Ba(OH)2 Ba2+ + 2OH- sb

H+ + OH- H2O

Ba2+ + SO42- + H+ + OH- H2O + BaSO4

Problem #4A solution of sodium hydroxide is added to a solution

of sodium dihydrogen phosphate until the same number of moles of each compound has been added.

NaOH Na+ + OH- sb

NaH2PO4 Na+ + H2PO4- salt

H2PO4- H+ + HPO4

2-

H+ + OH- H2O

H2PO4- + OH- H2O + HPO4

2-

Problem #5Dilute nitric acid is added to crystals of pure calcium

oxide.

HNO3 H+ + NO3- sa

CaO + H2O Ca2+ + 2OH-

2H+ + 2OH- 2H2O

CaO + 2H+ Ca2+ + H2O

Jump to Problem #8Excess sulfur dioxide gas is bubbles through a dilute

solution of potassium hydroxide.

KOH K+ + OH- sb

SO2 (NMO + H2O) HSO3-

HSO3- H+ + SO3

2-

H+ + OH- H2O

SO2 + OH- H2O + SO3

2-