Acids & Bases
Arrhenius Theory
-
HCl  H+ + Cl-
Acids produce H+ ions
Bases produce OH- ions
NaOH  Na+ + OH-
Bronsted- Lowry Theory
-
Acids donate protons (+)
Bases accept protons (+)
Acid + Base  Conjugate Acid + Conjugate Base
HCl
Acid
NH3
Base
+

H2O
Base
( in no particular order)
Cl-
Conjugate Base

+ H2O
Acid
+
Conjugate Acid
OH-
Conjugate Base
H3O+
+
NH4+
Conjugate Acid
Conjugate Acid – particle formed when a base gains a hydrogen ion.
Conjugate Base – particle that remains when an acid has donated a hydrogen ion
Conjugate acid-base pair – two substances that are related by the loss of gain of a single hydrogen ion
Ex: NH3 and NH4+
Acid
HCl
H2SO4
H3O+
Conjugate Base
Cl HSO4H2O
Base
NH3
H2O
Characteristics of Acids







Taste sour
pH from 0 – 6.99
has H+ at the beginning of the formula
produce H2 gas when reacting with most metals
neutralize bases
conducts electricity ( electrolyte)
turns litmus paper red
Conjugate Acid
NH4+
H3O+
Examples of Strong Acids
HCl
HBr
HI
H2SO4
HNO3
HClO3
HClO4
** the stronger an acid, the weaker its conjugate base and vice versa**
Characteristics of Bases



Taste bitter
pH between 7.01-14
have OH ions



feel slipper
ex. Soap
neutralize acids
turns litmus paper blue
Examples of Strong Bases
LiOH
NaOH
KOH
RbOH
CsOH
Mg(OH)2
Ca(OH)2
Sr(OH)2
Ba(OH)2
milk of magnesia
Naming Acids
Anion (ending)
-ide
-ite
-ate
Acid name
Hydro - ic
-ous
-ic
Monoprotic – has 1 H  HCl
Diprotic – has 2 H  H2SO4
Triprotic – has 3 H  H3PO4
Example
HCl  hydrochloric acid
HNO2  nitrous acid
HNO3  nitric acid
Anhydrides – acids of bases that have had H2O removed

Acidic anhydrides – produce an acid when dissolved in H2O
o Acid rain:
SO2(g) + H2O(l)  H2SO4(aq)

Basic anhydrides – produce a base when dissolved in H2O
o Na2O(s) + H2O(l)  2 NaOH(aq)
Neutralization Reactions
-
Always form a salt and water
Salt – a crystalline compound formed from an acid’s anion and a base’s cation.
HCl(aq) + NaOH(aq)  NaCl(s) + H2O(l)
Acid
base
Amphoteric – can act as either an acid of a base
Ex: H2O (water)
salt
water