Identify acids, bases, and salts. Describe the properties of an acid and a base. Define an indicator. Draw, label, and explain the pH scale. Use indicators to determine if an unknown is an acid, a base, or a salt. Describe a neutralization reaction. Complete neutralization reactions.

2. SBT
HOW TO TEACH
CHEMISTRY

3. Objectives
 Identify acids, bases and salts.
 Describe the properties of an acid and a base.
 Define an indicator.
 Draw, label and explain the pH scale.
 Use indicators to determine if an unknown is an
acid, a base, or a salt.
 Describe a neutralization reaction.
 Complete neutralization reactions.

4. Acids
 PROTON DONOR
 H+ ion
HCl -----→ H+ + Clˉ
H²S + NH³ ----→ NH⁴+ + HSˉ

5. Acids
 A. PROPERTIES OF ACIDS:
Sour taste
Litmus paper turns red
Reacts with metal to produce H gas
Contain H (most start with H)
Release H+ ion in solution (forms H30+)

6. Acids
B. STRONG ACIDS:
Produce H+ ions readily
Good electrolytes

7. Acids
B. STRONG ACIDS:
Produce many H+ ions
Good electrolytes
C. WEAK ACIDS:
Produce few H+ ions
Poor electrolytes

8. Bases
 PROTON ACCEPTOR
OH- ion
NaOH ----→ Na+ + OHˉ
H²S + NH³ ----→ NH⁴+ + HSˉ

9. Bases
 A. PROPERTIES OF BASES:
Bitter taste
Litmus paper turns blue
Slippery to the touch
Dissolve fats, oils, and grease
Most contain OH (hydroxide)
Most produce OH- ion in solution

10. Bases
B. STRONG BASES:
Produce OH- ions readily
Good electrolytes

11. Bases
B. STRONG BASES:
Produce OH- ions readily
Good electrolytes
C. WEAK BASES:
Produce few OH- ions
Poor electrolytes

12. Indicators
 Show a color change to identify an acid or
base
 Types:
1.Litmus paper
Red – acid
Blue – base

13. Litmus Paper Test

14. Indicators
2.Phenolphthalein
Clear – acid, neutral
Pink – base

15. Indicators
3. pH paper
Colors represent numerical values on pH
scale
Indicates acid, base, and neutral along with
strength

16. pH SCALE:
Range of numbers from 0 to 14
 Acid / base / neutral paper
Brown to Yellow – acid
Green – neutral
Blue to Purple – base

17. Activity

18. Activity
 Use litmus paper,
pH paper and other
indicators for measuring
pH of solutions.

19. Indicators
Sr# Indicator Colour in
acid
Colour in
Base
1 Litmus paper Red Blue
2 Methyl red Red Yellow
3 Bromothymol Blue Yellow Blue
4 Phenolphthalein Colourless Pink

20. Salts
 NEUTRALIZATION REACTIONS:
reaction between an acid and a base to
form a salt and water
 acid + base -----> salt + water
 HCl + Na(OH) -----> NaCl + H(OH)

21. Salts
 NEUTRALIZATION REACTIONS:
 reaction between an acid and a base to form a salt
and water
 acid + base ----->salt + water
 HCl + Na(OH) -----> NaCl + H(OH)
 HNO3 + Na(OH) -----> Na(NO3) + H(OH)