1. Acids and Bases
Acids are compounds that produce hydronium ions in water [H3O+] **that have H+ as the cation**
Sour taste
Reactivity with metals (single replacement)
Change blue litmus paper red
Bases are compounds that produce hydroxide ions in water [OH-] **that have OH– as the anion**
Bitter taste
Slippery feel
Change red litmus paper blue

2. Reactions and Strengths
Acid-Base interactions
when acids react with bases, they “neutralize” each other, producing a “salt” and water
reactions can be called “acid-base” or “neutralization” reactions
Acid-Base strengths can be described in two ways
the concentration of hydronium/hydroxide
the ease of formation of hydronium/hydroxide

3. Concentration of H3O+/OH-
The pH scale, ranging from 0 – 14, is related to the concentration of hydronium/hydroxide ions
acids have low pH, bases have high pH, and pH 7 is neutral
pH is a “logarithmic” scale with each unit represents a 10x change in concentration
pH Indicators
acids turn litmus paper red [red for “hot”]
bases turn litmus paper blue [blue for “base”]

4. Ease of Formation
Strong acids and bases = compounds that fully dissociate in solution
Strong acids – hydrochloric and sulfuric acids
Strong bases – sodium and potassium hydroxides
Weak acids and bases = compounds that partially dissociate in solution
Weak acid – carbonic and acetic acids
Weak base – ammonia

5. Buffers
A buffer solution resists changes in pH when acids or bases are added to the solution
Buffers can be created by mixing a weak acid or weak base and its salt
H2CO3 and CaCO3
NH4OH and NH4Cl
Buffers work because weak acids and bases are only partially dissociated
Thus, they are reversible reactions that are subject to Le Chatlier’s Principle (equilibrium)