CHAPTER 19 ACID, BASES & SALTS Open Textbook to page 586

MANY SUBSTANCES CONTAIN ACIDS. VINEGAR (ACETIC ACID) CARBONATED DRINKS (PHOSPHORIC ACID) GRAPE JUICE (TARTARIC ACID) APPLES (MALIC ACID) LEMONS (CITRIC ACID)

MANY SUBSTANCES CONTAIN BASES. LYE (SODIUM HYDROXIDE) FOUND IN COMMERCIAL DRAIN CLEANERS MILK OF MAGNESIA (MAGNESIUM HYDROXIDE) BAKING SODA (SODIUM BICARBONATE)

ACIDS: 5 GENERAL PROPERTIES: HAVE A SOUR TASTE. CHANGE THE COLOR OF ACID-BASE INDICATORS. REACT WITH ACTIVE METALS TO RELEASE H2 (g). Mg (s) + 2 HCl (aq)  MgCl2 + H2 (g)

REACT WITH BASES TO PRODUCE SALTS AND WATER. 5) SOME ACIDS CONDUCT ELECTRIC CURRENT.

ACID NOMENCLATURE BINARY ACID: ACID THAT CONTAINS ONLY 2 DIFFERENT ELEMENTS, i.e., HYDROGEN AND ONE OF THE MORE ELECTRONEGATIVE ELEMENTS.

NAMES OF BINARY ACIDS HF HYDROFLUORIC ACID HCl HYDROCHLORIC ACID HBr HYDROBROMIC ACID HI HYDROIODIC ACID H2S HYDROSULFURIC ACID

OXYACIDS ACID THAT IS A COMPOUND OF HYDROGEN, OXYGEN, AND a 3rd ELEMENT USUALLY A NONMETAL

COMMON OXYACIDS CH3COOH Acetic acid H2CO3 Carbonic acid HNO3 Nitric acid H3PO4 phosphoric acid H2SO4 sulfuric acid H2SO3 sulfurous acid HClO4 perchloric acid HClO3 chloric acid HClO2 chlorous acid HClO hypochlorous acid

Common Industrial Acids SULFURIC ACID: MOST COMMONLY PRODUCED INDUSTRIAL CHEMICAL USED IN CAR BATTERIES

NITRIC ACID: STAINS PROTEINS YELLOW USED IN MAKING EXPLOSIVES

PHOSPHORIC ACID: USED DIRECTLY FOR MANUFACTURING FERTILIZERS AND ANIMAL FEED. FLAVORING AGENT IN SOFT DRINKS

HYDROCHLORIC ACID: PRODUCED BY STOMACH IN HARDWARE STORES, DILUTE SOL’N KNOWN AS MURIATIC ACID AND IS USED TO CORRECT ACIDITY OF SWIMMING POOLS AND TO CLEAN MASONRY.

BASES 5 GENERAL PROPERTIES TASTE BITTER. CHANGE THE COLOR OF ACID-BASE INDICATORS. DILUTE AQUEOUS SOLUTIONS FEEL SLIPPERY.

BASES 5 GENERAL PROPERTIES REACT WITH ACIDS TO PRODUCE SALTS AND WATER. CONDUCT ELECTRIC CURRENT.

Svante Arrhenius Theory limited to aqueous solutions

ARRENHIUS ACIDS & BASES INCREASES THE CONC. OF HYDROGEN IONS, H+, IN AQUEOUS SOLUTIONS

ARRENHIUS ACIDS & BASES ARRENHIUS BASE: INCREASES THE CONCENTRATION OF HYDROXIDE IONS, OH-, IN AQUEOUS SOLUTIONS

AQUEOUS SOLUTIONS OF BASES ALKALINE IONIC HYDROXIDES WHICH DISSOCIATE IN SOLUTION TO RELEASE OH- (aq). SODIUM HYDROXIDE: NaOH NaOH (s)  Na+ (aq) + OH- (aq)

Group 1 Hydroxides NaOH KOH LiOH RbOH CsOH Group 2 Hydroxides Ca(OH)2 Ba(OH)2 Sr(OH)2

Another ACID-BASE THEORIES ARRENHIUS DEFINITION REQUIRES SUBSTANCES TO BE AQUEOUS. DEFINITIONS REVISED TO INCLUDE SUBSTANCES WHEN THEY ARE NOT IN A WATER SOLUTION.

BRONSTED-LOWRY ACIDS & BASES A MOLECULE or ION THAT IS A PROTON DONOR. HCl + NH3  NH4+ + Cl- HCl transfers a proton to the ammonia molecule

Figure 14.3 The Reaction of NH3 with HCl to Form NH4+ and Cl-

BRONSTED-LOWRY BASE MOLECULE OR ION THAT IS A PROTON ACCEPTOR.

The Reaction of NH3 with HCl to Form NH4+ and Cl- AMMONIA ACCEPTS A PROTON FROM HCl thus AMMONIA IS A BRONSTED-LOWRY BASE

BONSTED-LOWRY ACID-BASE REACTION PROTONS ARE TRANSFERRED FROM ONE REACTANT (THE ACID) TO ANOTHER (THE BASE).

ACID-BASE REACTIONS BRONSTED-LOWRY ACID DONATES A H+ SPECIES REMAINING COULD RE-ACCEPT THAT H+ AND THUS ACT AS A BASE

CONJUGATE BASE SPECIES THAT REMAINS AFTER A BRONSTED-LOWRY ACID HAS GIVEN UP A H+ ION. HF (aq) + H2O (l)  F- (aq) + H3O+ (aq) acid conjugate base

BRONSTED-LOWRY BASE ACCEPTS A H+ SPECIES REMAINING COULD RE-DONATE THAT H+ AND THUS ACT AS AN ACID

CONJUGATE ACID SPECIES THAT FORMS AFTER A BRONSTED-LOWRY BASE HAS ACCEPTED A H+ ION. HF (aq) + H2O (l)  F- (aq) + H3O+ (aq) base conjugate acid

Are equilibrium systems meaning that both the BRONSTED-LOWRY ACID-BASE REACTIONS Are equilibrium systems meaning that both the Forward and the reverse reactions occur. Each contain two conjugate acid-base pairs.

Let’s identify the Conjugate Acid-Base Pairs HNO3 (l) + H2O (l)  H3O+ (aq) + NO3- (aq)

Conjugate Acid/Base Pairs HA(aq) + H2O(l)  H3O+(aq) + A(aq) conj conj conj conj acid 1 base 2 acid 2 base 1 DO PROBLEM 48 on page 625

AMPHOTERIC COMPOUNDS SPECIES THAT CAN ACT AS EITHER AN ACID OR A BASE H2SO4(aq) + H2O  H3O+(aq) + HSO4- (aq) base NH3 (g) + H2O (l)  NH4+(aq) + OH- (aq) acid

Water as an Acid and a Base Water is amphoteric (it can behave either as an acid or a base). H2O (l) + H2O(l)  H3O+ + OH conj conj acid 1 base 2 acid 2 base 1

MONOPROTIC ACIDS ACIDS THAT CAN DONATE ONLY ONE HYDROGEN ION PER MOLECULE. EXAMPLES HCl HNO3 HClO4

Polyprotic Acids . . . can furnish more than one Hydrogen ion (H+) to the solution. Examples: H2SO4 H3PO4

All polyprotic acids ionize in a stepwise Manner i.e., one HYDROGEN ION at a time. H2SO4 (l) + H2O (l)  H3O+ (aq) + HSO4- (aq) HSO4- (aq) + H2O (l)  H3O+ (aq) + SO42- (aq) Each step is weaker than the one before; therefore, concentration of ions formed in the first step is the greatest.

POLYPROTIC ACIDS DIPROTIC ACID: CAN DONATE TWO HYDROGEN IONS PER MOLECULES. TRIPROTIC ACID: CAN DONATE THREE HYDROGEN IONS PER MOLECULE

Lewis Acids and Bases Emphasizes role of electron pairs to form a covalent bond Lewis Acid: electron pair acceptor Lewis Base: electron pair donor

The Al(H2O)63+ ion

Aluminum ion (Lewis Acid) accepts electron pairs From Water (Lewis Base) donates electron pairs to form covalent bonds. Lewis Acid-Base Reaction: formation of one or more covalent bonds between an electron-pair donor and an electron-pair acceptor.

LEWIS DEFINITION BROADEST OF THE THREE ACID-BASE DEFINITIONS

STRONG ACIDS ACID THAT IONIZES COMPLETELY IN AQUEOUS SOLUTION.

STRONG ACID Solutions MEMORIZE!!! HClO4 (aq) H2SO4 (aq) HNO3 (aq) HCl (aq) HBr (aq) HI (aq) MEMORIZE!!!

WEAK ACIDS ACID THAT IONIZES LESS THAN COMPLETELY IN AQUEOUS SOLUTION. . Ka is the acid dissociation constant. Smaller the Ka the weaker the acid.

Figure 14.4 Graphic Representation of the Behavior of Acids of Different Strengths in Aqueous Solution a) Strong Acid b) Weak Acid

Figure 14.6 A Strong Acid (a) and a Weak Acid (b) in Water

NaOH(s)  Na+(aq) + OH(aq) Bases “Strong” and “weak” are used in the same sense for bases as for acids. strong = complete dissociation (hydroxide ion supplied to solution) NaOH(s)  Na+(aq) + OH(aq)

Strong Bases (Strong electrolytes) Group 1A Hydroxides NaOH KOH LiOH RbOH CsOH Group 2A Hydroxides Ca(OH)2 Ba(OH)2 Sr(OH)2

WEAK BASES (Weak electrolytes): Weak = incomplete dissociation Kb is the base dissociation constant. Smaller the Kb the weaker the base. NH3 ammonia CH3NH2 methylamine Other organic compounds that contain nitrogen atoms.