HOBr is a weaker acid than HBrO3. Account for this fact.

Strong Acid/Weak Acid The number of oxygen atoms will effect the strength of the acid. HOBr has a single oxygen atom while HBrO3 contains three. The number of oxygen atoms will effect the strength of the acid. HOBr has a single oxygen atom while HBrO3 contains three. Oxygen is a very electro negative atom and will draw electrons away from the H-Br bond thus weakening the bond making it easier to dissociate when in dissolved in water. The more oxygen atoms the weaker the H-Br bond. Oxygen is a very electro negative atom and will draw electrons away from the H-Br bond thus weakening the bond making it easier to dissociate when in dissolved in water. The more oxygen atoms the weaker the H-Br bond. Charge of X Charge of X The charge on the X which in this case is the Br atom has a different charge in HOBr (+1) than in HBrO3 (+5) The charge on the X which in this case is the Br atom has a different charge in HOBr (+1) than in HBrO3 (+5) Strength of O-H Bond Strength of O-H Bond Strength of X-O Bond Strength of X-O Bond

Arrhenius Acid Base Concept Arrhenius Acid/Base Concept Acids produce Hydrogen ions (H+) within an aqueous solution Acids produce Hydrogen ions (H+) within an aqueous solution Bases produce Hydroxide Ions (OH-) in solution Bases produce Hydroxide Ions (OH-) in solution Definition is limited because it applies only to acids and bases that can dissociate OH- and H+ ions Definition is limited because it applies only to acids and bases that can dissociate OH- and H+ ions Examples: Examples: - NaOH will dissociate into Na+ and OH- - HCl will dissociate into H+ and Cl-

Bronsted-Lowry Model The model definition of Acid/Base The model definition of Acid/Base Bronsted Acid – A proton “donor” Bronsted Acid – A proton “donor” Bronsted Base – A proton “acceptor” Bronsted Base – A proton “acceptor” The definition applies to many more molecules that may exhibit Acid/Base qualities but do not directly produce OH- or H+ ions. The definition applies to many more molecules that may exhibit Acid/Base qualities but do not directly produce OH- or H+ ions. Every Acid and Base has a conjugate Acid or Base Every Acid and Base has a conjugate Acid or Base Water can act as an acid and a base Water can act as an acid and a base H 3 O+ (Hydronium ion) (acid) and OH- (Base) H 3 O+ (Hydronium ion) (acid) and OH- (Base)

Bronsted-Lowry Model Example of Bronsted Base Example of Bronsted Base NH 3(aq) + H 2 O (l)  NH 4 + (aq) + OH - (aq) NH 3(aq) + H 2 O (l)  NH 4 + (aq) + OH - (aq) Example of Bronsted Acid Example of Bronsted Acid HC 2 H 3 O 2(aq) + H 2 O (l)  H 3 O + (aq) + C 2 H 3 O 2 - (aq) HC 2 H 3 O 2(aq) + H 2 O (l)  H 3 O + (aq) + C 2 H 3 O 2 - (aq) Base Acid Conjugate Acid Conjugate Base Weak Acid Base Conjugate Acid Conjugate Base

Lewis Acid/Base Definition Lewis Acid/Base Definition Lewis Acid/Base Definition Lewis Acid – Electron Pair Acceptor Lewis Acid – Electron Pair Acceptor Lewis Base – Electron Pair Donor Lewis Base – Electron Pair Donor Encompasses an even wider variety of molecules (Bronsted and Arrhenius) even ones that do not donate protons or produce OH- ions. Encompasses an even wider variety of molecules (Bronsted and Arrhenius) even ones that do not donate protons or produce OH- ions. Must be aware of the Lewis structure of a particular molecule to determine whether it is a Lewis Acid or Base. Must be aware of the Lewis structure of a particular molecule to determine whether it is a Lewis Acid or Base.

Lewis Acid/Base Definition Examples Examples BF3(g) + NH3(g)  F3BNH3(g) BF3(g) + NH3(g)  F3BNH3(g) BF3 is the Lewis Acid because it has no free unpaired electrons with only has 6 electrons around the central atom (Boron will require one more pair of electrons to complete the valence shell) BF3 is the Lewis Acid because it has no free unpaired electrons with only has 6 electrons around the central atom (Boron will require one more pair of electrons to complete the valence shell) NH3 is the Lewis Base because the molecule has a completed octet valence shell with free unpaired electrons on the central atom. The BF3 will accept these unpaired electrons and form a covalent bond. NH3 is the Lewis Base because the molecule has a completed octet valence shell with free unpaired electrons on the central atom. The BF3 will accept these unpaired electrons and form a covalent bond.

Lewis Acid/Base Definition Example Example Ni2+(aq) + 6NH3(aq)  [Ni(NH3)6]2+(aq) Ni2+(aq) + 6NH3(aq)  [Ni(NH3)6]2+(aq) Ni2+ is the Lewis Acid because it is a cation which will attract negatively charged electrons to toward itself. Ni2+ is the Lewis Acid because it is a cation which will attract negatively charged electrons to toward itself. The NH3 is the Lewis Base because it provides the free unpaired electrons for the Ni2+ The NH3 is the Lewis Base because it provides the free unpaired electrons for the Ni2+

Lewis Acid/Base Definition Example Example Even earlier definitions are encompassed in the Lewis Acid Model Even earlier definitions are encompassed in the Lewis Acid Model H+ + H2O  H3O+ H+ + H2O  H3O+