ACIDSACIDS, BASESBASES, & SALTS

Properties of AcidsAcids1. Sour taste2. Electrolytes:

- aq solns that conduct electric current

3. React with bases to form water and salt (Neutralization Reaction)

4. React with most metals to produce H2(g)

5. Acidds turn litmus redd

ElectrolyteElectrolyte

• Substance when dissolved in H2O produces soln that conducts electric current– Separate into ions in aq soln

• Acids, bases, & salts are electrolytes

MgClMgCl22(s) (s) Mg Mg+2+2(aq) + 2Cl(aq) + 2Cl-1-1(aq)(aq)

Can metals react with acids?Can metals react with acids?

• See Table JTable J

• All metals above H2 react with acids

–SR reactions

• Cu, Ag, and AuCu, Ag, and Au do notnot react with acids

2HCl + Mg 2HCl + Mg

• Mg above H2 so reaction proceeds

• Single replacement reaction

MgClMgCl22 + H + H22

Properties of BasesBases

1. Bitter taste2. Slippery or soapy feeling3. Electrolytes4. React with acids to produce

water and salt5.5. BBases turn litmus bblue

Formulas of AcidsFormulas of Acids

• Format: HHX where X = nonmetal (F, Cl, Br, I) or or X = negative polyatomic ion Exception: H2O2

• Some acids have 2 or 3 HH’s–Ex: HHF, HH2S, HH3PO4

Formulas ofFormulas of BasesBases

• Format: MFormat: MOHOH

where M is metalwhere M is metal •Ex: NaOHOH, Ca(OHOH)2

• Exception: NH3 and NH4+1

• CH3OH is NOTNOT a base. WHY?WHY?

Identify the Electrolytes• NaClNaCl

• CC22HH55OHOH

• HH22SOSO44

• NaOHNaOH

• CC66HH1212OO66

• CaICaI22

• HFHF

• Mg(OH)Mg(OH)22

• CC33HH77OHOH

• CClCCl44

• HNOHNO33

• CC55HH1212

• KK33POPO44

• CHCH33OCHOCH33

• LiOHLiOH

• HIHI

• (NH(NH44))22SOSO44

• CC1212HH2222OO1111

Yes - SYes - S

Yes - SYes - S

Yes - SYes - S

Yes - BYes - B

NONO

NONO

NONO

NONO

NONO

NONO

NONO

Yes - Yes - AA

Yes - BYes - B

Yes - Yes - AA

Yes - BYes - B

Yes - Yes - AA

Yes - BYes - B

Yes - Yes - AA

Acid, Base, or Neutral?

• all HH22O contains some HO contains some H+1+1 & some OH & some OH-1 -1 ionsions–pure H2O: concentrations very low

• Neutral solution: [HNeutral solution: [H+1+1] = [OH] = [OH-1-1]]

• Acidic solution: HAcidic solution: H+1+1 > OH > OH-1-1

• Basic solution: OHBasic solution: OH-1-1 > H > H+1+1

Water & self-ionizationWater & self-ionization

• H2O(l) + H2O(l) H3O+1(aq) + OH-1(aq)

HH33OO+1 +1 = hydronium ion

OHOH-1-1 = = hydroxide ion

• H2O(l) H+1(aq) + OH-1(aq)

H+1 and H3O+1 used interchangeably

HH+1+1 called proton or hydrogen ion

Self-ionization of waterSelf-ionization of water

Arrhenius AcidArrhenius Acid• Substance that contains hydrogen & Substance that contains hydrogen &

ionizes to produce Hionizes to produce H+1+1 ions in aqueous ions in aqueous solutionsolution

HCl(g) + H2O(l) HH+1+1(aq) + Cl-1(aq)

HNO3 + H2O(l) HH+1+1(aq) + NO3-1(aq)

Arrhenius BaseArrhenius Base

• substance that contains hydroxide substance that contains hydroxide group & ionizes to produce OHgroup & ionizes to produce OH-1-1 ions in aqueous solutionions in aqueous solution

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

Arrhenius SaltArrhenius Salt

• Electrolytes where HElectrolytes where H+1+1 notnot only only positive ion and OHpositive ion and OH-1-1 notnot only only negative ion formed in aqueous negative ion formed in aqueous solutionsolution

Ex: NaCl, CaBr2,KNO3, NH4I

Salts in Water (ionic compounds)

• NaCl(s) + H2O(l) Na+1(aq) + Cl-1(aq)

• CaBr2(s) + H2O(l) Ca+2(aq) + 2Br-1(aq)

• Al(NO3)3(s) + H2O(l) Al+3(aq) + 3NO3-1(aq)

Arrhenius Model has limitationsArrhenius Model has limitations

• Don’t always use HH22O as solventO as solvent

– Arrhenius model only applies whenonly applies when H2O is solvent

• Doesn’t explain all cases:– NH3 (base) doesn’t contain OH-1 but it produces

OH-1

Alternate Theory: Bronsted-Alternate Theory: Bronsted-LowryLowry

• Acid = a proton donorAcid = a proton donor• All Arrhenius acids = Bronsted-Lowry All Arrhenius acids = Bronsted-Lowry

AcidsAcids

HX(g) + H2O(l) H3O+1 + X-1

HH+1+1 forms molecule-ion bond with water molecule HH33OO+1+1 (hydronium ion)hydronium ion)

Bronsted-Lowry Acids

• HCl + H2O H3O+1 + Cl-1

• HNO3 + H2O H3O+1 + NO3-1

• H2SO4 + H2O H3O+1 + HSO4-1

• H2O + HSO4-1 H3O+1 + SO4

-2

Bronsted-Lowry BaseBronsted-Lowry Base• Base = proton acceptorBase = proton acceptor

OH-1 is base

• Not restricted to aqueous solutionNot restricted to aqueous solution

NH3 + H2O NH4+1 + OH-1

NHNH33 is a base! is a base!

Bronsted-Lowry Acids & BasesBronsted-Lowry Acids & Bases

AmphotericAmphoteric

• Substance that acts as Substance that acts as both acid & baseboth acid & base

Water is amphoteric!Water is amphoteric!

HX(g) + H2O(l) H3O+1 + X-1 (base)

NH3 + HH22OO NH4+1 + OH-1

(acid)(acid)

Naming Acids & Bases

Naming Binary AcidsNaming Binary Acids

• Hydro + stem of nonmetal + icHydro + stem of nonmetal + ic

HF = ?

HCl = ?

H2S = ?

Hydrofluoric acidHydrofluoric acid

Hydrochloric acidHydrochloric acid

Hydrosulfic acidHydrosulfic acid

Naming Ternary Acids

• Name derived from polyatomicpolyatomic anion (see Table E)

• Replace –iteite with –ousous, add acid

HNOHNO22 • Replace –ateate with –icic, add, add acid

HNOHNO33

nitrous acidnitrous acid

nitric acidnitric acid

Ternary AcidsTernary Acids

polyatomics with S and P, make stem long againpolyatomics with S and P, make stem long again

– HH33POPO44 = phosphoric acid, not phosphic acid = phosphoric acid, not phosphic acid

– HH22SOSO44 = sulfuric acid, not sulfic acid = sulfuric acid, not sulfic acid

– HH22SOSO33 = sulfurous acid, not sulfous acid = sulfurous acid, not sulfous acid

•SEE TABLE KSEE TABLE K

NamingNaming BasesBases

• Name the metal + hydroxideName the metal + hydroxide

NaOH = ?

Ca(OH)2 = ?

Mg(OH)2 = ?

Sodium hydroxideSodium hydroxide

Calcium hydroxideCalcium hydroxide

Magnesium hydroxideMagnesium hydroxide