1. Handle acid with care!

2. Some everyday things that contain acids

3. In fact, we even have acid in our stomach!!!

4. What properties do acids have in common?
Sharp and sour taste.
Corrosive
pH less than 7

5. What is the meaning of acids?
An acid is a substance that produces ___________ when it dissolve in water.
hydrogen ions,H+

6. Acids only produce hydrogen ions in water.
without water
water
Acids only produce hydrogen ions in water.
Acids only show the properties of acids when they are dissolved in water.

7. This is because acids ionise in water.
add water
It is the hydrogen ions which are responsible for acidic properties.

8. HCl H2SO4 HNO3 H+ and Cl- H+ and SO42- H+ and NO3- Common acids:
Formula:
Ions produced:
Hydrochloric acid
HCl
H+ and Cl-
Sulphuric acid
H2SO4
H+ and SO42-
Nitric acid
HNO3
H+ and NO3-

9. What is the pH Scale? A scale which measures the degree of
acidity or alkalinity of an aqueous solution.
Ranges from 0 – 14.

10. pH of some common substances:1 2 3 4 5 6 7 8 9 10 11 12 13
pH = 14
pH = 0
Increasing
Acidity
Alkalinity
Neutral
HCL
Lemon Juice , Vinegar
Orange Juice
Acid Rain
Urine
Soft drink, Black Coffee
“Pure water”
Ammonia
Sea water
Baking Soda
Soap
Detergent
Sodium hydroxide

11. Solutions of pH less than 7 is acidic.1 2 3 4 5 6 7 8 9 10 11 12 13
pH = 14
pH = 0
Solutions of pH less than 7 is acidic.
The smaller the pH, the more acidic.
HCl
Soft drink
Solution of pH 7 is neutral
“Pure water”
Solutions of pH greater than 7 is alkaline.
The bigger the pH, the more alkaline.
Detergent
Sodium hydroxide

12. Indicator –is a chemical compound that is added in small amounts to a solution so that the pH (acidity or basicity) of the solution can be determined visually.
Common pH indicators:
Universal Indicator
Litmus paper
Phenolphthalein
Methyl orange
Different colours are observed in solutions depending whether it is:-
acidic
alkaline.

13. Type of Reactions of Acids:
reacts with
1. Metals
3. Metal Oxides
And
Hydroxides
(Neutralisation)
2. Carbonates

14. Summary (a) Acid and Metal metal + acid  salt + hydrogen
(b) Acid and Carbonate
carbonate + acid  salt + water + carbon dioxide
(c) Acid and Metal Oxide/ Hydroxide
(Neutralisation)
acid + base  salt + water

15. Not done yet!
So,what are the common alkalis used in our daily life?

16. Some everyday things that contain alkali

17. Perming solutions contain alkali which makes hair curly

18. What properties do bases have in common?
pH >7
Bitter taste.
Soapy feeling to the skin.

19. What is the meaning of bases?
solution of hydroxide ions, OH-are produced when bases
dissolve in water.
NaOH  Na OH-
Ca(OH)2  Ca OH –

20. Bases reactions BASES 1. Acids 2. Ammonium (Neutralisation) Salts
reacts with
1. Acids
(Neutralisation)
2. Ammonium
Salts

21. 1. Neutralisation reaction
Bases reacts with an acid to produce a salt and water
ACID + BASE --> SALT + WATER
HCl + NaOH > NaCl + H2O

22. Importance of pH:
pH of soil
pH of tank
pH of food

23. pH & Agriculture pH of soil
Excess acid in the soil can be neutralised by adding calcium hydroxide (slaked lime).
Farmers spread calcium hydroxide powder over their fields to neutralise acids.

24. The main active ingredient in household cleaning fluids.
CHEMICAL
NAME
FORMULA
DISSOLVE IN WATER
FOUND IN/USED FOR
Sodium
hydroxide
NaOH
Yes
Alkali
pH 13
Used to make soap.
Ammonia
NH3
pH 10
The main active ingredient in household cleaning fluids.
Calcium
Ca(OH)2
Used in agriculture to neutralise acidic soils.
Aluminium
Al(OH)3 No
Base
Used in some indigestion tablets.