ACIDSACIDS, BASESBASES, & SALTS

Properties of AcidsAcids1. sour taste2. electrolytes:

- aqueous solns 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 paper redd

ElectrolyteElectrolyte

• substance that dissolves in H2O to produce soln that conducts electric current

• acids, bases, & salts are electrolytes – form ions in H2O

HCl(s) H+1(aq) + Cl-1(aq)

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

NaCl(s) Na+1(aq) + Cl-1(aq)

Which metals react with acids?Which metals react with acids?

• See Table J

• All metals above H2 react with acids

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

2HCl + Mg MgCl2 + H2

• Mg above H2 so reaction proceeds

• single replacement reaction occurs

Properties of BasesBases

1. bitter taste2. slippery or soapy feeling3. Electrolytes4. react with acids to produce

water and salt5.5. bbases turn litmus paper bblue

Formula of Acid

• Format: HHX where X = nonmetal (F, Cl, Br, I)

or or X = negative polyatomic ion

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

Formula of Base

• Format: MOHOH where M is metal

•Ex: NaOHOH, Ca(OHOH)2

–exception: NH3 and NH4+1

• CH3OH is NOTNOT a base. 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 - SYes - S

NONO

NONO

NONO

NONO

NONO

NONO

NONO

Yes - AYes - A

Yes - BYes - B

Yes - AYes - A

Yes - BYes - B

Yes - AYes - A

Yes - BYes - B

Yes - AYes - A

Acid, Base, or Neutral?

• all H2O contains some H+1 and some OH-1 ions

– pure H2O: concentrations very low

• neutral solution: [H+1] = [OH-1]

• acidic solution: H+1 > OH-1

• basic solution: OH-1 > H+1

Water & 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 Acid• substance that contains hydrogen &

ionizes to produce HH+1+1 ions in (aq) soln

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

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

Arrhenius Base

• substance that contains hydroxide group & ionizes to produce OHOH-1-1 ions in (aq) soln

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

Arrhenius Salt

• electrolyte where H+1 not only (+) ion and OH-1 not only (-) ion formed in aqueous solution

Ex: NaCl, CaBr2,KNO3, NH4I

Salts in Water (ionic compounds)

• NaCl(s) Na+1(aq) + Cl-1(aq)

• CaBr2(s) Ca+2(aq) + 2Br-1(aq)

• KNO3(s) K+1(aq) + NO3-1(aq)

• NH4I(s) NH4+1(aq) + I-1(aq)

Arrhenius Model has limitations

• Don’t always use H2O as solvent

– Arrhenius model only applies when H2O is solvent

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

NH3(g) NH4+1(aq) + OH-1(aq)

Alternate Theory: Bronsted-Lowry

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

H+1

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

•HSO4-1 + H2O H3O+1 + SO4

-2

H+1

H+1

H+1

H+1

Bronsted-Lowry Base• Base is proton acceptorBase is proton acceptor

OH-1 is base

H+1 + OH-1 H2O

• not restricted to aqueous solution

NH3 + H2O NH4+1 + OH-1

NH3 is a base!

Bronsted-Lowry Acids & BasesBronsted-Lowry Acids & Bases

Amphoteric

• substance that acts as both acid & base

–H2O is amphoteric

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

NH3 + HH22OO NH4+1 + OH-1

(acid)(acid)

Water is amphoteric!Water is amphoteric!

Naming Acids & Bases

Naming Binary Acids

• Hydro + stem of nonmetal + ic

HF = ?

HCl = ?

H2S = ?

Hydrofluoric acid

Hydrochloric acid

Hydrosulfic acid

Naming Ternary Acids

• Name derived from polyatomicpolyatomic anion (see Table E)

• Replace –iteite with –ousous , add acid

HNO2 is nitrous acid• Replace –ateate with –icic, add, add acid

HNO3 is nitric acid

Ternary Acids

• polyatomics with S and P, make stem long again– H3PO4 = phosphoric acid, not phosphic acid

– H2SO4 = sulfuric acid, not sulfic acid

– H2SO3 = sulfurous acid, not sulfous acid

• SEE TABLE K

Naming Bases

• Name the metal + hydroxide

NaOH = ?

Ca(OH)2 = ?

Mg(OH)2 = ?

Sodium hydroxide

Calcium hydroxide

Magnesium hydroxide