Acids and Bases

1
Acids and Bases

• What are they?

2
Acids

• Hydrogen ions (H) in aqueous solution
• A solid or liquid hydrogen compound which
  dissociates in water and forms
• Hydronium ions (H3O)
• Ex. HCl(g) H2O(l) H3O Cl-
• An acid solution contains a great many hydrogen
  ions (protons) for transfer

3
Properties of Acids

• React with metals to form hydrogen gas Corrosive
  in high concentrations
• Can have sour taste
• Turn blue litmus paper red
• Neutralize bases
• pH below 7

4
Bases

• Hydroxide ions in solution (OH-)
• Sodium hydroxide to water leaves excess hydroxide
  ions
• NaOH H2O Na OH-
• Adding ammonia to water forms ammonium hydroxide
  as the ammonia accepts a proton from the water
  molecule
• NH3 H2O NH4 OH-
• Basic solutions contain a great many proton
  acceptors ready for protons.

5
Properties of Bases

• Unreactive with metals
• Bitter Taste (soap?)
• Slick to the touch (soapy?)
• Neutralize acids
• Turn red litmus paper blue
• pH above 7
• Make great cleaners, detergents, etc.

6
pH (power of Hydrogen)

• Also called the potential of Hydrogen
• log of the concentration of hydrogen ions
  (protons) per liter
• -log H
• Gives an easy view of the acidity of a solution
• Acids, Bases and pH

7
Neutralization

• Addition of either acid or base to a solution
  until acid and base are in perfect balance
  (equilibrium)
• Think of Tums, Rolaids, Mylanta, Gaviscon, Milk
  of Magnesia, Alka-Seltzer, Di-Gel, etc., etc.,
  etc. to an acid stomach
• Use the mole ratio from the balanced equation to
  calculate moles, molarity, and mass.
• Neutralization calculations

8
Titration

• Neutralization of an acid or base with a solution
  of known concentration
• Use the mole ratio to calculate
• Assignment Neutralization problem set