Acids & Bases Introduction.ppt for businees stufeens

short note

1. Prepared By, Mrs Yap-Wong Fui Yen

2. Handle acid
with care!

3. Some everyday things that contain acids

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

5. Sharp and sourtaste.
Corrosive
pH less than7
What properties do acids
have in common?

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

7. •Acids only produce hydrogen ionsin water.
water
without
water
•Acids only show the properties of acids when
they are dissolved in water.

8. •It is the hydrogen ionswhich
are responsible for acidic
properties.
•This is because acids ionise in
water.
add water

9. Common acids: Formula: Ions produced:
Hydrochloric acidHCl H
+
and Cl
-
Sulphuric acidH
2SO
4 H
+
and SO
4
2-
Nitric acid HNO
3
H
+
and NO
3
-

10. Experiment I: The pH Scale

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

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

13. 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.
Solutions of pH greater
than 7is alkaline.
The bigger the pH, the
more alkaline.
Solution of pH 7 is neutral“Pure water”
HCl
Sodium hydroxide
Detergent
Soft drink

14. Common pH indicators:
Universal Indicator
Litmus paper
Phenolphthalein
Methyl orange
Different coloursare
observed in solutions
depending whether it is:-
acidic
alkaline.

15. ACIDS
1. Metals2. Carbonates3. Metal Oxides
And
Hydroxides
(Neutralisation)
reacts with
Type of Reactions of Acids:

16. Dilute hydrochloric acid
(HCl)
Magnesium
ribbon
Acid Metal HydrogenSalt
Reaction 1: Acid with metals
+ +

17. Acid used: Salt produced:
Hydrochloric acid Chloride
Sulphuric acid Sulphate
Nitric acid Nitrate
Carbonic acid Carbonate

18. Magnesium + hydrochloric magnesium chloride
acid + hydrogen
Mg + 2HCl ----> MgCl
2+ H
2
Example:
Test:Use a burning/lighted
splinter to test
hydrogen gas.
Result:A ‘pop’sound is heard

19. Reaction 2: Acid with carbonate
Acidcarbonate saltcarbon dioxide+  +
water
+

20. Word Equation:
calcium + hydrochloric calcium chloride
carbonate acid + carbon dioxide
+ water
Chemical Equation:
CaCO
3+ 2HCl  CaCl
2+ CO
2 + H
2O
Example (2a):

21. copper(II) oxide + hydrochloric copper(II) cloride
acid +water
CuO + 2HCl ------> CuCl
2+ H
2O
Reaction 3: Acid with metal oxide/ hydroxide
Acid+
Metal oxide
/hydroxide
salt+water
This reaction is also known as
“neutralisation”.

22. 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

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

24. Some everyday things that contain alkali

26. Perming solutions contain alkali which
makes hair curly

27. Baking powder is alkaline

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

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

30. Most bases are insolublein water.
Bases that dissolve in water/ soluble are
called alkalis.
Insoluble bases Soluble bases
Magnesium oxide Sodium hydroxide
Copper(II) oxide Calcium hydroxide
Iron(II) oxide Ammonia
Is base similar to alkaline?

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

32. 1. Neutralisation reaction
Bases reacts with an acid to produce a salt
and water
ACID + BASE --> SALT + WATER
HCl + NaOH -----> NaCl + H
2O

33. Write a word and
symbol equation when
sulphuric acidreact
with sodium hydroxide?
H
2SO
4+ 2NaOH Na
2SO
4+ 2H
2O

34. 3. Alkali reacts with an ammonium salt.
Ammonium + sodium sodium chloride
chloride hydroxide +
water
+
ammonia gas
NH
4Cl + NaOH --> NaCl+ H
2O + NH
3
•Ammonia gasis produced.

35. Importance of pH:
pH of
food
pH of
soil
pH of
tank

36. 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 neutraliseacids.

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