This document discusses acids and bases. It defines acids as substances that produce hydrogen ions in solution, taste sour, and turn litmus paper red. Bases are defined as substances that produce hydroxide ions in solution, taste bitter, and turn litmus paper blue or green. Examples of common acids and bases are provided, along with their uses. The pH scale is introduced as a measure of whether a substance is acidic (pH less than 7) or basic (pH greater than 7). Salts are described as neutral compounds formed from acid-base reactions.

1. Acids and
Bases
Is a substance an
acid or a base?

2. Objectives:
Students should be able to:
• Describe the difference between
an acid and a base.
• Identify a substance as an acid or
base
•

3. ACIDS
An acid is a substance that:
• tastes sour
• reacts with metals and carbonates
• produces Hydrogen ions (H+) in a
solution
• turns litmus paper RED

4. USES OF ACIDS
• Citric acid and ascorbic acid (Vitamin C)
are found in orange juice
• Carbonic acid and phosphoric acid give a
“bite” to soft drinks
• Hydrochloric acid in your stomach aids in
digestion
•

5. BASES
A base is a substance that :
• tastes bitter
• feels slippery
• produces hydroxide ions (OH-) in a
solution
• turns litmus paper BLUE or GREEN

6. Uses of Bases
• Bases are used in soaps
(remember, bases are slippery)
• Bases are used to make paper,
oven cleaners, and to unclog drains
• Ammonia is a base and is used in
many household cleaners
• Medicines

7. Detecting Acids
and Bases
• You can detect an acid or a base
using an indicator.
• INDICATOR - A substance that
changes color in the presence of an
acid or a base.

8. INDICATORS
• Indicators:
Litmus paper
Cabbage juice
⮚An acid turns litmus paper red
⮚A base turns litmus paper blue or

9. HOW DO WE
MEASURE pH?

10. The pH Scale

11. pH
• If the pH is less than 7,
the substance is an acid
• If the pH is greater than
7, the substance is a base
•

12. Salts
-Large group of compounds with similar properties (usually formed with group 17, the Halogens)
-Neutralization reaction: the reaction between an acid and a base. Salt and water are produced.
NaOH + HCl NaCl + H2O
base + acid salt + water

13. Let’s see what you’ve
learned!

14. Question #1

15. Question #2

16. Question #3

17. Question #4

18. Question #5

19. Question #6

20. Acid or Base?
• HCl
• KOH
• HBr
• HNO3

21. Acid or Base?
• pH = 3
• pH = 8
• pH = 7
• pH = 5
• pH= 14