Acids, Bases, and Salts
Daelin Buford
Acid-Base Theories
Arrhenius
- Acids produce hydrogen ions (H^+) in aqueous solutions (HCl ----> H^+ - Cl^+)
- Bases produce hydroxide ions (OH^-) when dissolved in water (NaOH ----> Na^+ + OH^-)
Bronsted-Lowry
- Acid is a hydrogen-ion donor (H^+ or proton) (HCl is an acid)
- "Conjugated acid" is the particle formed when the original base gains a hydrogen-ion
- Base is hydrogen-ion acceptor (Water is a base)
- "Conjugated base" is the remainder of the original acid, after it donates its' hydrogen-ion
- NH3 + H2O ----> NH4^+ + OH^-
Lewis
- Lewis Acid- electron pair acceptor
- Lewis Base- electron pair donor
Calculating pH and pOH
[H^+]
- pH = -log[H^+]
- pOH = 14 - pH
pH
- [H^+] = 10^-pH
pOH
- [OH^-] = 10^-pOH
7 Strong Acids
- Sulfuric Acid = H2SO4
- Nitric Acid = HNO3
- Hydrochloric acid = HCl
- Hydrobromic acid = HBr
- Hydroiodic acid = HI
- Phosphoric acid = H3PO4
- Acetic Acid = HC2H3O2
4 Strong Bases
- Sodium Hydroxide = NaOH
- Potassium Hydroxide = KOH
- Barium Hydroxide = Ba(OH)2
- Calcium Hydroxide = CaOH
Naming Acids, Bases, and Salts
Binary Acid
- only two elements
- first element is hydrogen
- named--hydro______ic acid
- HCl = hydrochloric acid
Ternary Acid
- three elements
- first element is hydrogen
- other elements part of a polyatomic ion
- naming does NOT require a prefix
- ATE ----> IC
- ITE ----> OUS
- H2SO4 ----> sulfurIC acid
- H2SO3 ----> SulfurOUS acid
Naming Bases and Salts
- to name bases and salts, follow the standard rules for naming ionic compounds
- NaOH = sodium hydroxide
- CaCl2 = calcium chloride
Ka and Kb Expressions
Ka Expression
Ka = + -
(H ) (A )
Example
Equation: HNO2 ----> H^+ + NO2^-
Ka = [H^+] x [NO2^-]
[HNO2]
Kb Expression
Kb = (conjugate acid) x (OH^-)
(conjugate base)
Example
Kb = [M^+] [OH^-]
[MOH]