1. Acids and Bases

2. Bases Acids React with certain metals to produce hydrogen gas.
React with carbonates and bicarbonates to produce carbon dioxide gas
Bases
Have a bitter taste
Feel slippery.
Many soaps contain bases.

3. Properties of Acids
Produce H+ (as H3O+) ions in water (the hydronium ion is a hydrogen ion attached to a water molecule)
Taste sour
Corrode metals
Good Electrolytes
React with bases to form a salt and water
pH is less than 7
Turns blue litmus paper to red “Blue to Red A-CID”

4. Properties of Bases Generally produce OH- ions in water
Taste bitter, chalky
Are electrolytes
Feel soapy, slippery
React with acids to form salts and water
pH greater than 7
Turns red litmus paper to blue… “Basic Blue”

5. The pH Scale

6. pH and acidity
Acidity or Acid Strength depends on Hydronium Ion Concentration [H3O+]
The pH system is a logarithmic representation of the Hydrogen Ion concentration [H+] – used to avoid large numbers and powers.
In pure water [H3O+] = 1 x 10-7 mol / L (at 20oC)
 pH = - log(1 x 10-7) = - (0 - 7) = 7
pH range of solutions:
pH < 7 (Acidic)
pH > 7 (Basic)

7. Indicators

8. pH and acidity
The pH values of several common substances are shown at the right.
Many common foods are weak acids
Some medicines and many household cleaners are bases.

9. Neutralization
An acid will neutralize a base, making a salt and water as products
A salt is an ionic compound that is formed from the positive ion (cation) of the base and the negative ion (anion) of the acid

10. Neutralization Problems
Example 1: Hydrochloric acid reacts with potassium hydroxide. What are the products? Identify the product that is the salt.
HCl + KOH 
HCl + KOH  KCl + H2O
ACID BASE SALT DUH

11. Neutralization Problems
Example 2: Sulfuric acid reacts with sodium hydroxide. What are the products? Identify the product that is the salt.
H2SO4 + NaOH 
H2SO NaOH  Na2SO H2O
ACID BASE SALT DUH

12. Neutralization Problems
Example 3: Hydrochloric acid reacts with calcium hydroxide. What are the products? Identify the product that is the salt.
HCl Ca(OH)2 
2 HCl Ca(OH)2  CaCl H2O
ACID BASE SALT DUH

13. Acid Strength
Strong Acid - Transfers all of its protons to water Completely ionized Strong electrolyte
Weak Acid - Transfers only a fraction of its protons to water
- Partly ionized Weak electrolyte
As acid strength decreases, base strength increases.

14. Base Strength
Strong Base - all molecules accept a proton completely ionizes strong electrolyte
Weak Base - fraction of molecules accept protons partly ionized weak electrolyte
As base strength decreases, acid strength increases.

15. Common Strong Acids/Bases
Hydrochloric Acid
Nitric Acid
Sulfuric Acid
Phosphoric Acid
Hydrofluoric Acid
Hydrobromic Acid
Strong Bases
Sodium Hydroxide
Potassium Hydroxide
Calcium Hydroxide
Strontium Hydroxide
Rubidium Hydroxide
Lithium Hydroxide

16. Water as an Equilibrium System
Water has the ability to act as either an acid or base.
Water = H2O or HOH
H+ = acidic
OH- = basic

17. Salts A salt is the neutralization product of an acid and a base.
A salt is an ionic compound
The anion comes from the acid and the cation from the base.
Examples
HCl NaOH  NaCl + H2O.
H2SO4 + 2 KOH  K2SO4 + H2O.