Viewers, A very basic topic of chemistry for grade x is acid , bases and salts. A topic with lot of scope to add activities and make students understand better. Used all possibility to add colorful activities to explain concepts. Hope its beneficial for students. Dr MOna Srivastava Founder- Master chem Classes

1. CLASS-10
SUBJECT- CHEMISTRY
CHAPTER - ACIDS,BASES AND SALT
Dr. Mona Srivastava
M.Sc. Ph. D. Chemistry

2. *Period 1
*Learning objective
What are acid?
What are bases?
What are indicators ?

3. Where do we find acids and bases in daily life ?
Acids used in daily life Bases used in daily life

4. *What are acids and bases
*Acids
*Acids is defined as the one which produces hydrogen
ions in water.
*For Example, Sulphuric Acid, Hydrochloric Acid etc.
*They give sour taste.
*Acids turn blue litmus to red.
*Bases
*Bases are the one which produces hydroxide ions in
aqueous solutions
*They turn red litmus to blue.
*They have a bitter taste.

5. *Classification of acids
*1. Organic Acids-
* Acids which are derived from plants and animals, they
are known as Organic Acids.
*They are soft , less corrosive and harmless , derived from plants
and vegetables.
* Example - Citric acid, lactic acid, tartaric acid, malic acid etc.
*2. Mineral Acids-
* Mineral acids are inorganic in origin.
*Example- Sulphuric Acid, hydrochloric acid, nitric acid etc.
*They are dangerous to be used, so need more precautions.

6. Where do we find organic acids and bases??
Bases in common life -

7. *Classification of bases
*Bases are of 2 types –
*1. Strong base-
*Bases with greater concentration of hydroxyl ions in
them are called strong bases.
*E.g. NaOH, KOH, NH4OH
*2. Weak bases-
*Bases with lesser concentration of hydroxyl ions in
them are called strong bases.
*Fe(OH)2, Zn(OH)2, Mg(OH)2, etc.

8. *What are indicators
Indicators –
Indicators are those substances which show
different colors in acidic and basic medium
and there by help in identification of acids and
bases.
Types of indicators – 1. Natural indicators
– Indicators which are obtained from natural
sources are called natural indicators.
 2.Synthetic indicators-Indicators which are
prepared synthetically from laboratoties are
called natural indicators.

9. *Some natural indicators
1.Turmeric -Turmeric is yellow in neutral solutions. Turmeric
is yellow acidic solutions. Turmeric is red in basic solutions
2.China rose petals :China rose indicator is pink in neutral
solutions. China rose indicator is dark pink in acidic solutions.
China rose is green in basic solutions.
3.Litmus :It is a commonly used indicator. When added to
an acidic solution it turns red and when added to basic
solution it turns blue.
4.Red cabbage juice : Red cabbage juice turns blue in a
basic solution but it shows a distinct red colour in an acidic
solution.

10. CHINA ROSE EXTRACT
TUMERIC SOLUTION
SOME NATURAL INDICATORS
With acidic
solutions
With basic
solutions

11. Color change
reaction by red
cabbage solution

12. * How to test an acidic substance by china rose
indicator ??????
https://www.youtube.com/watch?v=r6kItfwar7Y
OPEN THIS LINK IN YOU YUBE

13. * Understanding the chemical properties of
acids and bases -

14. *Lets see a video to understand color
change reactions of indicators
https://www.youtube.com/watch?v=jEvhhxg2yKA
Open the link in you tube

15. *Olfactory Indicators
*Definition-
*There are some substances whose odour
changes in acidic or basic media. These are
called olfactory indicators. Examples -
Onion Extract Vanilla Extract Clove Oil

16. *Assignment no 1
Q.1 . Enlist 4 important properties of
acids.
Q.2. Enlist 4 important properties of
bases.
Q.3. what are indicators? Classify
them with suitable examples.

17. *Day - 6 ( P2 )
*Learning objective
Chemical reactions of acids with –
a. Metals
b. Carbonates
c. Bicarbonates
d. Metallic oxides
 Chemical reactions of
 bases with Metals

18. *Chemical reactions of acids
*1. Reaction of acids with metals
*Acid + active metal → salt + hydrogen + heat
*Example - Activity
*2HCl+Mg→MgCl2+H2 (↑)

19. *Video – How acids react with metals ????????
https://www.youtube.com/watch?v=9hBCLoWwcWo
Open the link in you tube

20. 2. Reaction of acids with carbonates
acid + metal carbonate → salt + water + carbon dioxide
Na2CO3(s) + 2HCl(aq) –> 2NaCl(aq) + H2O(l) + CO2(g)

21. 3.Reactions of acids with bicarbonates-
*Acid + Metal Bicarbonate → salt + water + carbon dioxide
*NaHCO3(s) + 2HCl(aq) –> 2NaCl(aq) + H2O(l) + CO2(g)
*Carbon dioxide reacts with lime turns the lime (Ca(OH)2) and
forms calcium carbonate. Calcium carbonate is insoluble in
water. It makes water milky.
*Ca(OH)2 (aq) + CO2(g) ——–> CaCO3(s) + H2O(l)
Milky
If CO2 is passed for a longer period then milky solution
turns clear due to the formation of soluble Calcium
bicarbonate which turns milky lime water clear.
*CaCO3(s) + CO2(g) + H2O(l)------>Ca(HCO3)2(aq.)

22. * Activity- how lime water turns milky by CO2
https://www.youtube.com/watch?v=Fgwl7lB_zKQ
open in you tube

23. 4.Reaction of metal oxides with acids
-
*Metal oxide + Acid Salt + Water
*Example-
*Copper oxide + hydrochloric acid Copper (ii) chloride + water
*CuCl 2 + HCl CuCl2 +H2O
*(When we add hydrochloric acid to copper oxide it gets
dissoled in it and a blue green solution is prepared.)

24. *Activity - Reaction of copper oxide with HCl
https://www.youtube.com/watch?v=VRJcn50b21A
Open in you tube

25. *Assignment no. 2
* Q. State with suitable chemical reaction what
happens when -
a. Acids react with metals.
b. Acids react with carbonates and
bicarbonates.
c. CO2 is passed through lime water for a
longer duration.

26. *Period 3
*Learning objective
Chemical reactions of bases with –
a. Metals
b. Non metallic oxides
Difference between alkali and bases
How do Acids and Bases React with each other?
(neutralization reaction)
What do all acids and all bases have in common?
What Happens to an Acid or a Base in a Water Solution?

27. Chemical reactions of bases-
*1. Reactions of bases with metals-
*Base + metal → salt + hydrogen + heat
* 2 NaOH+Zn→Na2ZnO2+H2 (↑)
Sodium zincate
*Note - A more reactive metal displaces the less reactive
metal from its base.
* 2 Na+ Mg (OH) 2→2 NaOH + Mg

28. 2.Reactions of bases with nonmetallic oxides -
*The bases react with nonmetallic oxides as follows –
*Base + Non-metal oxide → salt + water + heat
*2NaOH + CO2→ Na2CO3 + H2O
*Non-metal oxides are
acidic in nature.
Note - when metallic
oxides react with acids
the resulting solution is
basic while when bases
react with nonmetallic
oxides resulting solution
is acidic.

29. Difference between alkali and bases

30. * How do Acids and Bases React with each other?
(neutralization reaction)
*The reaction between an
acid and a base to give a salt
and water is known as a
neutralization reaction. In
general, a neutralization
reaction can be written as –
*Base + Acid Salt +
Water
*NaOH(aq) + HCl(aq)
NaCl(aq) + H2 O(l)

31. What do all acids and all bases have in common?
*All acids have similar chemical properties that they
generate hydrogen gas on reacting with metals, so
hydrogen seems to be common to all acids.
* When acid is added to distilled water , electricity starts
flowing , due to the presence of H+ ions.
*All bases do contain hydroxyl groups but only water
soluble bases ( alkalis ) only generate hydroxyl ions in
water .
*If alkali is added to distilled water , electricity starts
flowing through it due to the presence of OH- ions .

32. What Happens to an Acid or a Base in a
Water Solution?
*When acid dissolves in water, they donate hydrogen ions
(H+).
*If a solution has a high concentration of H
+
ions, then it is
acidic.
* Ex. HCl + H2O ➡ (H3O)+
+ Cl –
*Note- H+
ion cannot exist alone and hence combines with
water molecules and form (H3O)+
.
* When base dissolves in water solution produces OH- ion.
* NaOH(s) Na+
(aq) + OH (aq)
* If a solution has a high concentration of OH
-
ions, then it
is basic.

33. *Assignment no 2
*Q.1. Why do HCl, HNO3 , etc., show acidic characters in
aqueous solutions while solutions of compounds like
alcohol and glucose do not show acidic character?
*Q.2.Why does an aqueous solution of an acid conduct
electricity?
* Q.4 .Why does dry HCl gas not change the color of the
dry litmus paper?
* Q.3. How is the concentration of hydronium ions
(H3O+) affected when a solution of an acid is diluted?

34. PERIOD 3
*Learning objective –
Strength of acids and bases-
 Need for measuring scale of strengths of acids and bases.
 pH scale , use of pH paper.
 Concept of universal indicator
 pH Of some common solutions

35. Measurement of the strength of acids and bases
What do you mean by strength of acids and
bases????
Strong acid or base: When all molecules of a given
amount of an acid or a base dissociate completely
in water to furnish their respective ions, H
+
(aq) for
acid and OH−
(aq) for base.
Weak acid or base: When only a few of the
molecules of a given amount of an acid or a base
dissociate in water to furnish their respective ions,
H
+
(aq) for acid and OH
−
(aq) for

36. Lets understand by this picture-------

37. * pH Scale - A need for the measurement of
strength of acids and bases .
*In order to measure and express the strength a logarithmic scale
pH ( power/ potential of hydrogen ) was introduced by SORENSON.

38. What are Litmus paper and universal indicator
??
A. Litmus Paper –
 Litmus is extracted from plant LICHENS.
The main use of litmus is to test whether a solution is acidic
or basic .
Blue litmus paper gets turned red under acidic conditions .
Red litmus paper gets turned blue under basic or alkaline
conditions.
2. Universal indicator -
A universal indicator is a pH indicator made of mixing several
indicators ( of different ranges of pH) which can exhibit the
 color changes over a wide range pH values of different
solutions.
 Its available in the form of - 1. solution 2. pH paper .

39. How to use pH paper / universal indicator for
the detection of ph??????

40. Universal indicator and its color change

41. Color of solution and pH information

42. Showing pH of some day to day products

43. * Video - How universal indicator works
https://www.youtube.com/watch?v=_FQYC2I-FtM
Open in you tube

44. *Assignment no. 3
Q.1 . Explain why is hydrochloric acid a strong acid
and acetic acid, a weak acid. How can it be verified?
Q.2. You have four solutions A, B, C and D. The pH
of solution A is 6, B is 9, C is 12 and D is 7,
 (a) Identify the most acidic and most basic
solutions.
 (b) Arrange the above four solutions in the
increasing order of H+ ion concentration.
 (c) State the change in color of pH paper on dipping
in solution C and D.

45. *PERIOD 4
Learning objective-
 Importance and application of p H value in daily life for –
 Fertility of soil-
 Human metabolism -
 Protection of tooth decay -
 Chemical self defense in insects -

46. Plants and animals are pH sensitive
Living organism can
survive in a narrow range
of pH ie 7.0 to 7.8.
 The survival of aquatic
animals becomes difficult
when pH of rain water
( acid rain) is less than 5.6
or during acid rain.
The acid rain flows into the
rivers, it lowers the pH of
the river water.

47. Role of pH and fertility of soil -
Plants require a specific pH range ( 6.5 to 7.5) for their
healthy growth.
Soil pH is a characteristic that describes the relative
acidity or alkalinity of the soil.
Soils are considered acidic if pH < 5.
 soils are considered alkaline if pH > 7.5.
By spreading the suitable chemicals on soil the pH of the
soil can be maintained.

48. pH and human digestive system
Stomach produces Hydrochloric acid.
 It helps in the digestion of food without harming the
stomach.
During indigestion the stomach produces
too much acid and this causes pain and irritation
causing the problem of ACIDITY.
To overcome this problem ANTACIDS are given
which contain bases which neutralize the excessive
acids being produced and relives us from irritation,
stomach pain and headache as its side effects.
The ANTACIDS commonly contain milk of
magnesia (magnesium hydroxide) in
them.

49. How does antacid work??????
Acidity causes burning sensation
antacids

50. Protection of tooth decay
Tooth decay starts when the pH of the mouth is less than
5.5.
Tooth enamel, made up of calcium phosphate is the hardest
substance in the body.
Its insoluble in water but at pH 5.5 it dissolves in the water
Bacteria present in the mouth produce acids by degradation
of sugar and food particles remaining in the mouth after
eating.
Using toothpastes, which are generally basic ( contain
sodium fluoride and sodium carbonate)for cleaning the
teeth can neutralize the excess acid and prevent tooth decay
The best way to prevent this is to clean the
mouth after eating food.

51. How to save enamel of teeth
https://www.youtube.com/watch?v=vkeCV0rhdyw
Open in you tube

52. Chemical self defense in insects
The sting of bees contain
formic acid, which they
use for chemical self
defense as well as
catching the prey .
It causes swelling, skin
inflammation and
irritation if the bee
injects the sting inside
your skin.
In order to neutralize ,
the use of baking soda in
affected place proves to
be effective as it
neutralizes the acid .

53. *Period 5
*Learning objectives-
*Chemicals from Common Salt –
1. Sodium hydroxide
2. Bleaching powder
3. Baking soda ( sodium hydrogen carbonate)
4. Washing soda
5. Plaster of Paris

54. Common salt ( sodium chloride NaCl)
*Common salt – It is obtained from the sea
water and is the source of many important
salts of commercial use.
*Common salt is the raw material for following
compounds-
1) Sodium hydroxide
2) Bleaching powder
3) Baking soda ( sodium hydrogen carbonate)
4) Washing soda
5) Plaster of Paris

55. * Preparation of sodium hydroxide-
*NaOH is produced by electrolytic dissociation of NaCl (called
brine), it gets decomposed to form sodium hydroxide.
*The process is called the Chlor -Alkali Process because of the
products formed – chlor for Cl2 and alkali for NaOH.
2NaCl(aq) + 2H2O(l) 2 NaOH (aq) + Cl2 (g) + H2 (g)
We get 3 products -
1. Cl2 gas is released at the anode.
2. H2 gas is released at the cathode.
3. NaOH solution is formed near the cathode.
Sodium hydroxide ( NaOH )

56. Uses of Cl2 , H2 and NaOH
CHEMICAL USES
1. Chlorine Water treatment, in
swimming pools, PVC, CFC
etc.
2. Hydrogen Fuels , ammonia , fertilizers
3. NaOH In greasing metals,
preparing soaps, detergents,
paper and Synthetic fibers

57. 2. Bleaching powder
*Preparation of bleaching powder-
*Cl2 gas (produced during electrolysis of sodium
chlodire) is used for the manufacture of bleaching
powder.
* When Cl2 is treated with dry slaked lime [Ca(OH)2]
bleaching powder is produced.
*It is represented as CaOCl2 , though the actual
composition is quite complex.
*Ca(OH) + Cl 2 CaOCl 2 + H2O

58. Uses of bleaching power
In Textile industry –
1. For bleaching cotton and linen .
2. For bleaching washed clothes in laundry;
In paper industry - For bleaching wood pulp in paper industry.
In Chemical industry – As oxidizing agent in many reactions.
 As disinfectant - As disinfectant in drinking water to make it free
of germs.

59. 3.Baking soda ( sodium hydrogen carbonate)
Preperation - It is produced using sodium chloride as one
of the raw materials.
*NaCl + H2O + CO2 + NH3 NH4Cl + NaHCO3
(Ammonium (Sodiumhydrogen
- chloride) - carbonate)
It is a mild non corrosive salt .
 During cooking when its heated , gives following reaction –
 2 NaHCO3 Na2CO3 + H2 O + CO2
(Sodium hydrogencarbonate) (Sodiumcarbonate)

60. Uses of sodium hydrogen carbonate-
1. As baking powder - It is a mixture of baking soda
(sodium hydrogen carbonate) and a mild edible acid such as
tartaric acid. When baking powder is heated or mixed in water,
the following reaction takes place –
NaHCO3 + H+ CO2 + H2O + Sodium salt of acid
(From any acid)
Carbon dioxide produced during the
reaction causes bread or cake to rise
making them soft and spongy.
2. Ingredient for antacids which
neutralizes the excessive acid produced
in stomach and provides relief.
3. In soda-acid fire extinguishers.

61. *Washing soda (sodium carbonate)
Preparation of washing soda –
Obtained by heating baking soda , and then
recrystallization of sodium carbonate gives washing soda.
Na2CO3 + 10H2O Na2CO3.10 H2O
(Sodium carbonate) ( washing soda)
It is a basic salt .
Note – 10 Water molecules
attached to the compound
are known as water
of crystallization.

62. Uses of washing soda
*Uses of washing soda are as follows –
(i) Industrial uses- Used in glass, soap and paper industries.
(ii) In the manufacture of sodium compounds-
It is used in the manufacture of important sodium compounds
such as borax.
(iii) As cleaning agent –
Used as a cleaning agent for domestic purposes.
(iv) As an agent for removing permanent hardness-
It is used for removing permanent hardness of water.

63. Plaster of Paris
* Preparation –
*It is prepared from gypsum CaSO4 .2HO
*On heating gypsum at 373 K, it loses water molecules and becomes
Calcium sulphate hemihydrate ( CaSO4. 1/2 H2O )
Heat / 373K
CaSO4.2H2O CaSO4.1/2 H2O + 1 ½ H2O
Gypsum Plaster of Paris

64. What happens when plaster of Paris comes in
contact with water??
*Plaster of Paris is a white powder and on mixing with water,
it changes to gypsum once again giving a hard solid mass.
CaSO4.1/2 H2O +1 ½ H2O CaSO4.2H2O
(Plaster of Paris) (Gypsum)
The doctors use Plaster of Paris for supporting fractured
bones in the right position in the form of plaster.

65. Assignment no 5
Q.1.What is the common name of the compound CaOCl2?
Q.2. Name the substance which on treatment with chlorine yields
bleaching powder.
Q.3. Name the sodium compound which is used for softening
hard water.
Q.4.What will happen if a solution of sodium hydrogen carbonate
is heated? Give the equation of the reaction involved.
Q.5.Write an equation to show the reaction between Plaster of
Paris and water.

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