Acids and Bases

SC Physical Science Standard

PS-3.8Classify various solutions as acids or bases according to their physical properties, chemical properties (including neutralization and reaction with metals), generalized formulas, and pH (using pH meters, pH paper, and litmus paper).

Acids and Bases

Acids produce H+ in solutions

HCl H+(aq) + Cl- (aq)

Bases produce OH- in solutions

NaOH Na+(aq) + OH-

(aq)

H20

H2O

Determining pH

pH- a measurement of hydrogen ion concentrationpH scale ranges from 0 – 14pH of an acid is 0 – 7

Acids have more H+ than OH-.

The lower the pH the more acidic the solution.

pH of a base is 7 – 14Bases have less H+ than OH-.

The higher the pH the more basic the solution.

pH of neutral is 7Neutral has equal H+ and OH-.

Neutral is neither acid nor base.Water is neutral.

Determining pH

pH is tested for two ways:1. pH meter- gives a digital reading of the pH of a solution2. indicator- a compound that turns different colors based on the pH of the solution it is in (example: litmus paper, phenolphthalein)

Properties of Acids

-Produce H+ (H3O+) in solution

-Formulas start with H

- Taste sour

-Neutralize bases

-Corrosive to skin and tissue

-Acids turn litmus paper red

Corrosive to metals-react with metals to produce hydrogen gas

Are electrolytes in solution-conduct electricity

Common Acids

Acetic Acid - HC2H3O2 - Vinegar

Folic acid - orange juice

Phosphoric acid - H3PO4 - soda

Ascorbic acid - vitamin C - citrus fruits

Hydrochloric acid -HCl - stomach acid

Sulfuric Acid-H2SO4

- Car batteries, industry

Properties of BasesProperties of Bases

-Produce OH- in solution

-Have OH in formula

-Taste bitter

- Neutralize acids

-Corrosive to skin and body tissues

-Turn Litmus paper blue

Feel slippery

Electrolytes in solution

Common Bases

Mg(OH)2

Magnesium hydroxideantacids

NH3 Ammonia cleaners; fertilizer

Ca(OH)2 Calcium Hydroxidealso in fertilizers (lime)

NaOHSodium hydroxideDrano

Al(OH)3

Aluminum hydroxideAntiperspirants

Acid – Base Neutralization

Neutralization-The process of Acids and Bases reacting to form a Salt and Water.

This is called neutralization because the in forming water, the H+ and the OH- are equal in solution.