The document discusses the properties and reactions of acids, bases, and salts, highlighting their definitions, uses, and chemical behaviors. It covers topics such as acid-base indicators, neutralization reactions, pH scale, and real-life applications like digestion and common household products. Additionally, it explains the processes for making substances like sodium hydroxide and bleaching powder from common salt.

1. ACIDS , BASES AND SALTS
CHAPTER
3
X - CLASS
PHYSICAL SCIENCE
By:
RAVI KALYANKAR

2. What have we learnt ?
 Acids are sour to taste, Turn
blue litmus to red
 Bases are soapy to touch,
Turns red litmus to blue

3. BLUE LITMUS
RED LITMUS
WHAT IS THERE IN LITMUS WHICH IS
RESPONSIBLE FOR THE COLOUR CHANGE???

4.  We use natural and chemical indicators to
test acids and bases. So they are called
acid-base indicators
 Acid-base indicators are dyes or mixer of
dyes which are used to indicate the
presence of acids and bases

5. Litmus solution is dye extracted from lichen, a plant
belonging to the division of a Thallophyte.
Litmus are dye molecules which are weak acids or
bases. They are used as acid , base indicators to detect
that a particular solution is acid or base

6. ACID – BASE INDICATOR
NATURAL SYNTHETIC

7. Chemical Properties Of Acids
ACID
M
e
t
h
y
l
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a
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g
e
p
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SAMPLE ACIDS
Red litmus Red
Blue litmus Red
Methyl
orange
Red
phenolphtha
lein
No change

8. Chemical Properties Of Bases
BASE
M
e
t
h
y
l
o
r
a
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g
e
p
h
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o
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p
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SAMPLE BASES
Red litmus Blue
Blue litmus Blue
Methyl
orange
Yellow
phenolphtha
lein
pink

9. REACTION OF ACID AND BASES WITH METAL
Acid + Metal --------------------> Salt + Hydrogen
2HCl + Zn --------------------->ZnCl2 + H2
Base + Metal ------------------->Salt + Hydrogen
2NaOH + Zn ------------------>Na2ZnO2 + H2

10. REACTION OF ACID AND BASES WITH METAL
NOTE: Burning splinter is put off by making a pop
sound indicates the presence of H2 gas

11. REACTION OF ACIDS WITH CARBONATES AND METAL
HYDROGEN CARBONATES
METAL CARBONATE + ACID ---------------->SALT + CARBON DIOXIDE + WATER
Na2CO3(s) + 2HCl(aq) ----------------> 2NaCl(aq) + H2O(l) + CO2(g)
METAL HYDROGEN CARBONATE + ACID ------>SALT + CARBON DIOXIDE + WATER
NaHCO3(s) + HCl(aq) ----------------> NaCl(aq) + H2O(l) + CO2(g)
Pass the gas evolved through lime water
Ca(OH)2(aq) + CO2(g) ----------------> CaCO3↓ + H2O(l)
On passing excess carbon dioxide the following reaction takes places
CaCO3(s) + H2O(l) + CO2(g) ------------------------->Ca(HCO3)2(aq)
(WHITE PRECIPITATE)
(SOLUBLE IN WATER)

12. Neutralization reaction
BASE + ACID --------------------> SALT + WATER
NaOH(aq) + HCl(aq) ----------------> NaCl(aq) + H2O(l)
METAL OXIDE + ACID -----------> SALT + WATER
CuO + 2HCl --------------> CuCl2 + H2O
NON-METAL OXIDE + BASE ------------> SALT + WATER
 METAL OXIDES
ARE BASIC IN
NATURE
 NON-METAL
OXIDES ARE
ACIDIC IN
NATURE

13. WHAT DO ACIDS-BASES HAVE IN COMMON
Acids in water conduct electricity. Because of
Hydrogen ions and Bases produce Hydroxide
ions
Acidic nature of substance is due to the
formation H+
(aq) in solution, formation of OH-
(aq) ion in solution is responsible for the basic
nature of solution
Bases in water conduct electricity because of
OH-
ions.
In Glucose and alcohol ions are absent
Acid and Base solutions have ions and the
electric current is carried though the
movement of ions

14. WHAT DO ACIDS-BASES HAVE IN COMMON
Note: Bases which are soluble in water are
called alkalis
Some examples of Acids:
HCl, H2SO4, HNO3, CH3COOH
Some examples of Bases:
NaOH, KOH, Mg(OH)2, NH4OH,Ca(OH)2

15. DO ACIDS PRODUCE IONS ONLY IN AQUEOUS
SOLUTION????

16. DO ACIDS PRODUCE IONS ONLY IN AQUEOUS
SOLUTION????
2NaCl(s) + H2SO4(l) -------------------->2HCl(g) + Na2SO4(s)
HCl + H2O ------------> H3O+ + Cl-
Hydrogen ions cannot exist as bare ions. They attach with water
molecule and exist as hydrated ions with each H+
attached by 4 to 6
water molecules.

17. DO ACIDS PRODUCE IONS ONLY IN AQUEOUS
SOLUTION????
NaOH(s) -----------------> Na+
(aq) + OH-
(aq)
On dissolving bases in water produces hydroxide(OH)-
ions
Bases which are soluble in water are called alkalis
All bases do not dissolve in water Be(OH)2 is slightly soluble in water

18. What happens, when water is mixed with
acid or base ????
• The process of dissolving an acid or a
base in water is an exothermic
process.
• Mixing an acid or base with water
results in dilution
HCl

19. Warning sign
 The warning sign is present on the
can of concentrated sulphuric acid
and on the bottle of sodium
hydroxide pellets.
 It indicates that this should be
handled with care, otherwise it may
cause burns.

20. STRENGTH OF ACID OR BASE
 Strong acids are completely ionized
where as weak acids are partially
ionized.
Strong acid HCl
weak acid  CH3COOH
 Strong bases release more OH-
ions
in water, where as weak bases
release less OH-
ions in water.
strong base  NaOH
weak base  NH4OH

21. UNIVERSAL INDICATOR
The strength acid or a base can be tested using
universal indicator
Universal indicator is mixer of several indicators
It shows different colors at different concentration
of Hydrogen ion in a solution
pH scale ----------->Universal indicators

22. pH scale
• Sorensen introduced the concept of pH.
• pH means ‘power of Hydrogen’
• The pH scale is from 0-14
• A neutral solution has a pH of 7, while an acidic solution has a pH less than 7
and a basic solution has a pH more than 7.
• A mixture of several indicators is called Universal indicator

23. Importance of pH in everyday life
• Living beings carry out their metabolic activities within an optimal pH range
• Our body works within the pH ranges of 7.0 to 7.8
• When pH of rain water is less than 5.6, it is called acid rain
• pH of soil is also essential for the healthy growth of plants

24. pH change cause of tooth decay
• Tooth decay starts when the pH of the
mouth is lower than 5.5
• Tooth enamel made of calcium
phosphate, the hardest substance in the
body gets corroded
• Using toothpaste generally basic
neutralize the excess acid and prevent
tooth decay

25. pH in our digestive system
 Our stomach produces Hydrochloric acid
which helps in digestion of food without
harming stomach
 During indigestion the stomach produces
too much acid and this causes pain and
irritation
 So antacids are the bases used to control
the stomach pain causes due to
indigestion
 Magnesium hydroxide(Mg(OH)2) is known
as the ‘milk of magnesia’

26. Self defense by animals and plants through
chemical was fare???
Use of mild
base like
baking soda
on the stung
area gives
relief

27. Nettle plant
Stinging hair of leaves ------> methanoic acid ------>burning pain

28. Dock plant
Relieves
pain

29. salts
Salts are ionic compound formed when acid combines with a
base
This reaction is called neutralization reaction
Salts are electrically neutral
Sea water contains many salts dissolved in it, among them
sodium chloride is a predominant component
A B --------------> A+
+ B-
cation anion

30. FAMILY OF SALTS Sodium family
NaNO3 Na2CO3
NaCl Na2SO4
Chloride salt family
NH4Cl NaCl
Potassium sulphate ------------>K2SO4
Calcium sulphate -------------> CaSO4
Copper sulphate -------------->CuSO4
Sodium nitrate ------------> NaNO3
Ammonium chloride----------> NH4Cl
Sodium sulphate ------------> Na2SO4
Magnesium sulphate ---------> MgSO4
Sodium carbonate ------------->Na2CO3
Sodium chloride --------------> NaCl
Sulphate salt family
K2SO4, CaSO4, CuSO4, MgSO4, Na2SO4
Carbonate salt family
Na2CO3, MgCO3, CaCO3
Magnesium carbonate ------------> MgCO3
Calcium carbonate ------------>CaCO3

31. pH of salts
Acid Base Salt pH Acidic Basic Neutra
l
H2SO4 KOH K2SO4 <7 YES - -
H2SO4 Ca(OH)2 CaSO4 <7 YES - -
H2SO4 Cu(OH)2 CuSO4 <7 YES - -
HNO3 NaOH NaNO3 >7 - YES -
HCl NH4OH NH4Cl <7 YES - -
H2SO4 NaOH Na2SO4 7 - - YES
H2SO4 Mg(OH)2 MgSO4 >7 - YES -
HCl NaOH NaCl 7 - - YES
H CO NaOH Na CO >7 - YES -

32. Common salt – a raw material for chemical
Common salt is otherwise called as
table salt
Its chemical composition is NaCl
The deposits of solid salt are found in
several parts of the world
These deposits of large crystals are
often brown due to impurities. This is
called as ‘rock salt’

33. Common salt – a raw material for chemical
Beds of rock salts are formed when
seas of bygone ages dried up
Salts have various uses in everyday
life and in industries
The common salt is an important raw
material for various materials of daily
use, such as sodium hydroxide, baking
soda , washing soda, bleaching
powder etc.

34. Sodium hydroxide from common salt
• Sodium hydroxide is prepared by a
process called as chloro-alkali process
• Because of the products formed
chloro for chlorine and alkali for
sodium hydroxide
• Electricity is passed through an
aqueous solution of sodium
chloride(brine)
• Chlorine gas is given off at the anode
and hydrogen gas at the cathode, the
three products produce in this
process are all useful

35. Sodium hydroxide from common salt

36. Bleaching Powder
Bleaching powder is produced by the action of chlorine on
dry slaked lime [ca(OH)2].
It is represented by formula CaOCl2
Chlorine is produced during the electrolysis of aqueous
sodium chloride(brine) .
This chlorine gas is used for the manufacture of bleaching
powder.
Ca(OH)2 + Cl2 -------------> CaOCl2 + H2O

37. Uses of Bleaching Powder
Used as an oxidizing agent in many
chemical industries
Used for disinfecting drinking water to
make it free of germs
Used for bleaching cotton and lines in
the textile industry
Used bleaching wood pulp in paper
industry
Used for bleaching washed clothes in
laundry

38. Baking soda
The chemical name of the compound is sodium hydrogen
carbonate(NaHCO3)
NaCl + H2O + CO2 + NH3 ----------->NH4Cl + NaHCO3
Baking soda is a mild non-corrosive base
when it is heated it forms sodium carbonate
2NaHCO3 --------------> Na2CO3 + H2O + CO2
Baking soda is sometimes added for faster cooking

39. Uses of Baking soda
Baking powder is a mixture of baking soda and a mild
edible acid.
When baking powder is heated or mixed in water,
carbon dioxide is produced during the reaction causes
bread or cake to rise making them soft and spongy
NaHCO3 + H+
------------->CO2 + H2O + sodium salt of acid

40. Uses Baking soda
Sodium hydrogen carbonate is an
ingredient in antacids
Being alkaline, it neutralizes
excess acid in the stomach and
provides relief
It acts as mild antiseptic
It is used as soda-acid in fire
extinguishers

41. Washing soda
It is obtained from sodium chloride
Sodium carbonate can be obtained by heating baking
soda
Its chemical formula is Na2CO3.10H2O (washing soda)
Recrystallisation of sodium carbonate gives washing
soda
Na2CO3 + 10H2O ------------>Na2CO3.10H2O
It is a basic salt

42. Uses of Washing soda
 It is used in glass, soap and paper industry
 It is used in the manufacture of sodium
compounds such as borax
 It is used for removing permanent hardness of
water
 It is used as cleaning agent for domestic
purpose

43. Removing water of crystallization
 Water of crystallization is the fixed
number of water molecules present in
one formula unit of a salt.
 Five water molecules are present in
one formula unit of copper
sulphate(CuSO4.5H2O)
 Another salt which possesses water of
crystallization is gypsum
 It has two water molecules in its
crystals and the formula is
CaSO4.2H2O

44. Plaster of Paris
 On heating gypsum(CaSO4.2H2O) at 373K it loses water molecules
partially to become calcium sulphate hemihydrate(CaSO4.1/2H2O)
 This is called plaster of Paris
CaSO4.1/2H2O + 1 1/2H2O --------------> CaSO4.2H2O
 Plaster of Paris is a white powder, on mixing with water , it sets into
solid mass due to the formation of gypsum

45. Plaster of Paris
Uses:
 Making toys
 Materials for decorations
 Making surfaces smooth
 Supporting fractured bones
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