The document discusses acids and bases. It defines acids as compounds that ionize in water to produce hydrogen ions, and bases as compounds that react with acids to produce salts and water. Alkalis are bases that ionize in water to produce hydroxide ions. Water is necessary for acids and alkalis to exhibit their properties, as it allows them to dissociate into ions. The document also outlines the chemical properties of acids and bases, such as their reactions with each other, metals, and carbonates to produce salts, water, hydrogen gas or carbon dioxide. Common uses of acids and bases in daily life are also mentioned.

3. 7. ACIDS AND BASES

4. 7.1 Analysing Characteristics And
Properties Of Acids And Bases
LEARNING OUTCOME :
 State the meaning of acid, base and alkali
 State the uses of acids, bases and alkalis in daily life
 Explain the role of water in the formation of hydrogen ions to show properties of acids
 Explain the role of water in the formation of hydroxide ions to show the properties of
alkalis
 Describe the chemical properties of acids and alkalis
7.1.1 State the meaning of acid, base and alkali

5. In 1884 . . .
 A Swedish Chemist, Arrhenius
proposed that compounds can be
classified into two :
 Acids and Bases

6. According to Arrhenius . .
AN ACID IS A CHEMICAL COMPOUND
THAT IONIZE IN WATER TO PRODUCE
HYDROGEN IONS, H+
7.1.1 State the meaning of acid, base and alkali

7.  In this reaction, hydrochloric acid
(HCl) dissociates completely into
hydrogen (H+) and chlorine (Cl-)
ions when dissolved in water,
thereby releasing H+ ions into
solution.
HCl (aq) → H+ (aq) + Cl− (aq)

8.  The hydrogen ions combines with a water molecule,
H2O to form hydroxonium ion, H3O+
HCl(aq) + H2O(l) → H3O+(aq) + Cl−(aq)
8
7.1.1 State the meaning of acid, base and alkali

9. The Relationship between
H+ and H3O+ :
7.1.1 State the meaning of acid, base and alkali

10. Example of acids in the lab :
Hydrochloric acid, HCl Nitric acid, HNO3
Sulfuric acid, H2SO4
7.1.1 State the meaning of acid, base and alkali

11. BASICITY OF ACID
 Basicity : the number of ionisable
hydrogen atoms per molecule of an
acid.
 Monoprotic acid : produces one
mole of hydrogen ion when ionises
in water
 Examples of monoprotic acid : HCl
 Diprotic acid : produces two moles
of hydrogen ion when ionises in
water
 Examples of diprotic acid : H2SO4
7.1.1 State the meaning of acid, base and alkali

12. Next, what is bases and alkalis ?
ACCORDING TO ARRHENIUS,
A BASE IS A CHEMICAL
SUBSTANCE WHICH REACT WITH
ACID TO PRODUCE SALT AND
WATER.
AN ALKALI IS A BASE WHICH
IONISES IN WATER TO PRODUCE
HYDROXIDE IONS, OH-
EXAMPLE : NAOH, KOH, NH3
7.1.1 State the meaning of acid, base and alkali
Acid + Base Salt + Water

13. Most bases dissolves in water.
These soluble bases are called alkalis.
EXAMPLES OF ALKALIS :
SODIUM HYDROXIDE AMMONIA
NaOH → Na+ + OH-
NH3 + H2O → NH4
+ + OH-
7.1.1 State the meaning of acid, base and alkali

16. ROLE OF WATER ON THE PROPERTIES OF
ACIDS
7.1.1 Explain the role of water in the formation of hydrogen ions and hydroxide ions
 An acid shows its acidic properties only in the presence of water
 Water is essential for the formation of hydrogen ions that cause the acidity
 In the absence of water, dry acids or acids dissolves in organic solvents
DO NOT SHOW any acidic property because the acids exists as molecules
and are not dissociated into hydrogen ions

17. ROLE OF WATER ON THE PROPERTIES
OF ACID
Acids
Pure acid / acid in organic
solvent consists of covalent
molecules only. H+ is not
present.
Eg:
Dry/glacial ethanoic acid,
Ethanoic acid in propanone
Acid only show their acidic
properties in the presence of
water.
7.1.3 Explain the role of water in the formation of hydrogen ions to show properties of acids

18. To investigate role of water on the
properties of acid
Blue
litmus
paper
Glacial ethanoic acid
Blue litmus
paper
Glacial ethanoic acid
+
distilled water
Glacial ethanoic
acid +
Propanone
Blue
litmus
paper
A
B
C
7.1.3 Explain the role of water in the formation of hydrogen ions to show properties of acids

20. ROLE OF WATER ON THE PROPERTIES OF
ALKALIS
7.1.1 Explain the role of water in the formation of hydrogen ions and hydroxide ions
 An alkali shows its alkaline properties only in the presence of water
 Water is essential for the formation of hydroxide ions that cause the
alkalinity.
 In the absence of water, alkali exists as molecules and does not show any
alkaline properties

21. ROLE OF WATER ON THE
PROPERTIES OF ALKALI
Alkali
Pure alkali in the dry
state does not exhibit
alkaline properties -
No hydroxide ions.
Alkali only show
their alkaline
properties in the
presence of water.
7.1.4 Explain the role of water in the formation of hydroxide ions to show properties of alkalis

22. ROLE OF WATER ON THE PROPERTIES OF
ACID/ALKALI
Acids
Pure acid / acid in organic
solvent consists of covalent
molecules only. Hydrogen ion,
H+ is not present.
Eg: Dry/glacial ethanoic acid,
Ethanoic acid in propanone
Acid only show their
acidic properties in
the presence of water.
Alkali
Pure alkali in the dry
state does not
exhibit alkaline
properties - No
hydroxide ions, OH-
Alkali only show
their alkaline
properties in the
presence of water.
7.1.1 Explain the role of water in the formation of hydrogen ions and hydroxide ions

23. Uses of Acids, Bases and Alkalis in daily life :
 Acids and bases are widely used in our daily life in agriculture,
medicine, industry and preparation of food
7.1.2 State the uses of acids, bases and alkali in daily life.

24. Uses of Acids in daily life :
 Acids and bases are widely used in our daily life in agriculture,
medicine, industry and preparation of food
7.1.2 State the uses of acids, bases and alkali in daily life.
Sulphuric acid in
Lead-acid accumulator
Tartaric acid in
Baking powder
Nitric acid in
Plant fertilizers

25. Uses of Bases in daily life :
 Acids and bases are widely used in our daily life in agriculture,
medicine, industry and preparation of food
7.1.2 State the uses of acids, bases and alkali in daily life.
Sodium hydroxide in
soaps and detergents
Aluminium hydroxide in
gastric medicine
Magnesium hydroxide in
toothpaste

26. Properties of
Acid/Alkali
Taste
pH value ?
Solubility in
water?
Does it change
the color of
litmus paper?
Can it conduct
electricity? Why
Color of
acid/alkali?

27. Properties of
Acid
Sour taste
pH value
less than 7
Soluble in
water
Turns blue
litmus paper to
red
Can
conduct
electricity
Colorless
solution

28. Properties of
Alkali
Bitter taste
pH value
more than 7
Soluble in
water
Turns red litmus
paper to blue
Can conduct
electricity
Colorless
solution

29. leenl@
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Explain the following:
A solution of hydrogen chloride in toluene does not react
with marble whereas a solution of hydrogen chloride in
water does.
[6 marks]
7.1.1 State the meaning of acid, base and alkali

30. leenl@
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(b) In toluene the hydrogen chloride exist as covalent molecules
There are no hydrogen ions present in the solution. Thus the solution
does not show acidic properties. When dissolved in water, the
hydrogen chloride molecules dissociate to produce hydrogen ions.
HCl  H+ + Cl-
The hydrogen ions will react with marble to release carbon
dioxide gas. (1)
2H+ + CaCO3  Ca2+ + CO2 + H2O
7.1.1 State the meaning of acid, base and alkali

31. TO INVESTIGATE ROLE OF WATER ON THE
PROPERTIES OF ALKALI
Filter
funnel
Distilled water /
trichloromethane
Anhydrous calcium oxide
7.1.1 State the meaning of acid, base and alkali

32. What are the products when . .
 Acids react with base
 Acids reacts with metals
 Acids reacts with carbonate
 Alkali reacts with acids
 Alkali reacts with metal ions
 Alkali reacts with ammonium
salts

33. CHEMICAL PROPERTIES OF ACID
 Acids can react with base to form salts and water.
Acid + Base Salt + Water
H2SO4 (aq) + ZnO (s) ZnSO4 (aq) + H2O (l)
 Acids can react with metals to produce salts and Hydrogen gas.
Acid + metal Salt + hydrogen gas
2HCl (aq) + Mg (s) MgCl2 (aq) + H2 (g)
 Acids can react with carbonates to produce salt, water and carbon dioxides
Acid + Carbonates Salt + Water + Carbon dioxides
2HNO3 (aq) + CuCO3 (s) Cu(NO3)2 (aq) + H2O (l) + CO2 (g)

34. Chemical Properties of Acid
acid + base  salt +
water
H2SO4 + ZnO → ZnSO4
+ H2O
Acid + Metal →
Salt + Hydrogen
2HCl + Mg →
MgCl2 + H2
Acid + carbonate metal → Salt
+ water + carbon dioxide
2HCl + CaCO3 → CaCl2 + CO2
+ H2O
Acid
Alkali
Acid
Metal
Burning
wooden
splinter
Calcium
carbonate
acid
Lime
water

35. CHEMICAL PROPERTIES OF ALKALI
 Alkali react with acids to form salts and water.
Alkali + Acid Salt + Water
NaOH(aq) + HCl(s) NaCl(aq) + H2O(l)
 Most metal hydroxides are insoluble in water. Hence, adding an alkali to most metal
ions solutions will give a precipitate of an insoluble metal hydroxide
Alkali + metal Insoluble metal hydroxides
2OH-(aq) + Cu2+(aq) Cu(OH)2(s) (blue precipitate)
 When a mixture of an alkali and an ammonium salt is heated, ammonia gas is
liberated along with salt and water.
Alkali + Ammonium Salt Salt + Water + Ammonia gas
NaOH(aq) + NH4Cl (aq) NaCl(aq) + H2O (l) + NH3 (g)

36. Chemical Properties of Alkali
Alkali + acid  salt +
water
NaOH + HCl  NaCl + H2O
Alkali + ammonium
salt  salt + water +
ammonia gas
NaOH + NH4Cl 
NaCl + H2O + NH3
Alkali + metal ion  insoluble
metal hydroxide
2OH- + Cu2+  Cu(OH)2 (s)
Acid
Alkali
Alkali +
ammonium salt
Red litmus
paper
ammonia
Heat
Metal ion
+ alkali

37. Activity 7.1
TO INVESTIGATE THE
CHEMICAL PROPERTIES OF ACIDS
Apparatus : Test tube, test tube holder, spatula, Bunsen
burner, delivery tubes with stopper, wooden
splint
Materials : 1.0 mol dm-3 sulphuric acid, copper(II) oxide,
zinc powder, sodium carbonate powder and
lime water

38. Let’s recap!
 Define acid.
 Give 1 example of acid
 What is a monoprotic acid?
 Give an example
 What is a diprotic acid?
 Give an example
 Without water, acids and alkali exists as ______.
 Acids will ______ in the presence of water.
 Alkalis will ________ in the presence of water.
 Define base.
 Define alkali.
 Give 2 examples of alkali
 Acid + Base = Salt + Water
 Acid + Metal = Salt + Hydrogen Gas
 Acid + Carbonates = Salt + Water + Carbon dioxide
 Alkali + Metal ions = Metal hydroxide
 Alkali + Ammonium Salt = Salt + Water + Ammonia
Gas

39. 7.1 Analysing Characteristics And
Properties Of Acids And Bases
LEARNING OUTCOME :
 State the meaning of acid, base and alkali
 State the uses of acids, bases and alkalis in daily life
 Explain the role of water in the formation of hydrogen ions to show properties of acids
 Explain the role of water in the formation of hydroxide ions to show the properties of
alkalis
 Describe the chemical properties of acids and alkalis

40. Quick Review
1. Using a suitable examples, state the meaning of
a) Acid
b) Base
c) Alkali

41. Quick Review
1. Write an equation to show how dilute sulphuric acid,
H2SO4 reacts with
a) Magnesium, Mg
b) Zinc oxide, ZnO
c) Copper(II) carbonate, CuCO3

42. Quick Review
1. Potassium hydroxide, KOH must be dissolved in water
so that it shows its alkaline properties. Explain the role
of water in this situation

43. Quick Review
1. Briefly describe how potassium hydroxide, KOH reacts
with
a) hydrochloric acid, HCl
b) iron(III) chloride, FeCl3 solution
c) ammonium chloride, NH4Cl solution

44. Quick Review
1. Briefly describe how potassium hydroxide, KOH reacts
with
a) hydrochloric acid, HCl
b) iron(III) chloride, FeCl3 solution
c) ammonium chloride, NH4Cl solution

49. CHEMICAL PROPERTIES OF ACID
Indicator Color of indicator in
acidic solution
Blue litmus paper Red
Universal Indicator Orange and red
Methyl orange Red
 Acids can react with :
1. Acid + Base Salt + Water
2. Acid + Metals Salt + Hydrogen Gas
3. Acid + Carbonates Salt + Water +
Carbon dioxides

50. CHEMICAL PROPERTIES OF ALKALI
 Acid tastes BITTER, feel soapy
 Acid solution have pH value more than 7
 Acids change colors of indicators :
Indicator Color of indicator in
acidic solution
Blue litmus paper Blue
Universal Indicator Blue or purple
Methyl orange Yellow
 Acids can react with :
1. Acid + Base Salt + Water
2. Acid + Metals Salt + Hydrogen Gas
3. Acid + Carbonates Salt + Water + Carbon
dioxides

52. 7.2 The Strength of Acids and Alkalis
LEARNING OUTCOME :
 State the uses of a pH scale
 Relate pH values with acidic or alkaline properties of a substance
 Relate the concentration of hydrogen ions with pH values
 Relate the concentration of hydroxide ions with pH values
 Relate strong or weak acids with the degree of ionisation
 Conceptualize qualitatively strong and weak acids
 Conceptualize qualitatively strong and weak alkalis

53. How to determine the pH of a solution?
 We can use pH meter, pH strips or Universal Indicator
pH meter
pH strips Universal
Indicator

54. Uses of pH scale
To indicate the degree of acidity or alkalinity of
a solution
Consists of pH values that range from 0 to 14.
pH less than 7 : acidic solution
pH equals to 7 : neutral solution
pH more than 7 : alkaline solution

55. Strength of ACIDS & BASES

56. Strength of ACIDS & BASES
Acidic Increases Alkaline Increases
Strong Acid
(Low pH)
Weak Acid
(High pH)
Weak Alkali
(Low pH)
Strong Alkali(High
pH)
Ionises completely in
water - high
concentration of
hydrogen ions.
Eg: HCl, HNO3 , H2SO4
Ionises partially in water
- low concentration of
hydrogen ions.
Eg: Ethanoic acid,
CH3COOH
Ionises completely in
water - high
concentration of
hydroxide ions.
Eg: NaOH, KOH
Ionises partially in water -
low concentration of
hydroxide ions
Eg: ammonia, NH3

57. Strong and Weak Acids
 The strength of an acid depends on the degree of
ionisation or degree of dissociation of the acid in
water.

58. Strong and Weak Acids
 Strong acid dissociates COMPLETELY in water.
 Complete dissociation (100%) of acid produces HIGH
CONCENTRATION of H+ ions
 For example HCl is a strong acid. When HCl is dissolved in
water, H2O it completely dissociates into H+ (aq) and Cl-(aq)
ions. ALL the HCl molecules become ions

59. Strong and Weak Acids
 A weak acid ionises partially (incomplete dissociation) in
water.
 Dilute ethanoic acid, CH3COOH is an example of weak acid.
 The incomplete ionisation is indicated by a reversible sign.
 The ethanoic acid molecules are still present in the acid as the
ions combine again to form the original acid molecules.

60. Strong and Weak Acids
Dissociate completely in water
Dissociate partially in water

61. Acid A has a pH of 1.2
Acid B has a pH of 4.7
Which acid is stronger? Why?
Try this!
Acid A

62. Try this!
1. What is the use of the pH scale?
To indicate the degree of acidity or alkalinity of a
solution
2. If a solution is acidic, can u predict the pH value?
pH < 7
3. Solution B has a pH of 13. Solution X is
____________ solution.
an alkali

63.  The pH value is actually a measure of the
concentration of hdyrogen ions, H+ and hydroxide
ions, OH-.
 The HIGHER THE CONCENTRATION OF H+ IONS, the
LOWER the pH
 The HIGHER THE CONCENTRATION OF OH- IONS,
the HIGHER the pH

64. Higher concentration
of H+ ions,
lower pH
Higher concentration
of OH- ions,
higher pH

65. Higher concentration
of H+ ions,
lower pH
Acid A
Which acid is
STRONGER?

66. Strong and Weak Alkalis
 The strength of an alkali depends on the degree of
ionisation/ degree of dissociation of the alkali in water.

67. Strong and Weak Alkalis
 A strong alkali is COMPLETELY ionised in water.
 Sodium hydroxide, NaOH is a strong alkali. It will
IONISE COMPLETELY when dissolved in water.
 Only sodium ions, Na+ and hydroxide ions, OH- are
present in the solution.

68. Strong and Weak Alkalis
 A weak alkali IONISES PARTIALLY in water.
 Ammonia, NH3 is an example of weak alkali.
 Only a SMALL AMOUNT of ammonia, NH3 molecules
are ionised in water to produce ammonium ions, NH4+
and hydroxide ions, OH-.

69. Strong and Weak Alkalis
Dissociate completely in water
Dissociate partially in water
alkali
alkali

70. Acid base indicator
Indicator Colour in
ACID SOLUTION
Colour in
ALKALINE SOLUTION
Litmus paper
Red Blue
Phenolphthalein
Colorless Pink
Methyl orange
Red Yellow

71. CONCENTRATIONS OF
ACIDS AND ALKALIS

72. 7.3 Analysing concentration of acids and
alkalis
LEARNING OUTCOME :
 State the meaning of concentration,
 State the meaning of molarity,
 State the relationship between the number of moles with
molarity and volume of a solution,
 Describe methods for preparing standard solutions,
 Describe the preparation of a solution with a specified
concentration using dilution method,
 Relate pH value with molarity of acid and alkali,
 Solve numerical problems involving molarity of acids and alkalis

73. CONCENTRATION
 The concentration of a solution determines the amount of
solute dissolved in a given volume of solution.
 The greater the amount of solute dissolved, the higher the
concentration of the solution.

74. Concentration of a solution
 Refers to the quantity of solute in a given volume of
solution
 Quantity of solute can be measured in grams or
moles.

75. Concentration of a solution
 Unit : molarity (mol dm-3)
Molar concentration (M)
 Molarity is the number of moles of solute that are
present in 1 dm-3 of a solution.

76. Concentration of acids & alkalis
 Quantity of solute in a given volume of solution
 unit : molarity (mol dm-3) or
molar concentration (M)
Solute (g) + water (dm3)

77. Relationship between concentration and
molarity
concentration
(g dm-3)
Molarity
(mol dm-3)
÷ molar mass
x molar mass
*Refer to examples in text book page 124.

78. Try this!
1. Find
a) The concentration of a solution in grams per dm3
when 36.5 g of hydrogen chloride, HCl is dissolved in
water to make up 500cm3 of solution.
b) The molarity of a solution which is prepared by
dissolving 0.30 mole of sodium hydroxide, NaOH in
distilled water to make up 250cm3 of solution.

79. Try this!
1. Find
a) The concentration of a solution in grams per dm3
when 36.5 g of hydrogen chloride, HCl is
dissolved in water to make up 500cm3 of solution.

80. Try this!
1. Find
a) The concentration of a solution in grams per dm3
when 36.5 g of hydrogen chloride, HCl is
dissolved in water to make up 500cm3 of solution.
1. Convert volume of solution from cm3 to dm3
2. 1 dm3 = 1000 cm3
3. Calculate the concentration

81. Try this!
1. Find
a) M
b) The molarity of a solution which is prepared by
dissolving 0.30 mole of sodium hydroxide, NaOH
in distilled water to make up 250cm3 of solution.

82. Try this!
The molarity of a bottle of nitric acid, HNO3 solution
is 2.0 mol dm-3. What is the concentration of the
solution in g dm-3?
[Relative atomic masses : H, 1; N, 14; O, 16]
*Refer to concentration formula.
What information do u have?

83. Number of moles of solute = Molarity x Volume of solution
(mol) (mol dm-3) (dm3)
n = MV
Molarity

84. Concentrations of acids and alkalis
M = Concentration in mol dm-3 [Molarity]
V = Volume in cm3
1000 cm3 = 1 dm3
No. of mol
MV_
1000
84

85. leenl@
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Calculation involving concentrations of solutions in g/dm3
Concentration is the amount / quantity of solute dissolves in a given volume of solution
which is usually 1 dm3 of solution.
It can be expressed in
- g/dm3.
- mol/dm3 this unit is also called molarity of the solution
1. 5.0 g of copper (II) sulphate is dissolved in water to form
500 cm3 solution. Calculate the concentration of copper(II)
sulphate solution in g/dm3.

86. leenl@
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SOLUTION
 Information :
Mass of copper(II) sulphate = 5.0g
Volume of solution = 500 cm3 = 0.5 dm3
 Hence, concentration (g/dm3) of copper (II) sulphate solution
=(5.0g ÷ 0.5 dm3)
= 10.0 g/dm3

87. leenl@
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1. What is the mass of sodium carbonate required to dissolve
in water to prepare a 200cm3 solution that contains 50
g/dm3?
 Volume of solution = 200 cm3 = 0.2 dm3
 Concentration (g/dm3)
=[(mass of Na2CO3 dissolved (g)] ÷ [volume of solution (dm3)]
Hence, mass of Na2CO3 required
= concentration (g/dm3) x volume of solution (dm3)
= 50 g/dm3 x 0.2 dm3
= 10 g

88. leenl@
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Calculation involving concentrations of solutions in mol/dm3
Molarity, M (mol/dm3) = No. of moles of solute, n (mol)
Volume of solution, V (dm3)
No. of moles,n (mol) = Molarity (M) x Volume (V) dm3
OR
No. of moles (mol) = Molarity (M) x [Volume (V) / 1000 cm3 ]
= MV/1000

89. leenl@
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1. A 250cm3 nitric acid solution contains 0.4 moles. Calculate the
molarity (M) of the nitric acid.
2. Calculate the number of moles (n) of ammonia in 150 cm3 of 2
mol/dm3 aqueous ammonia?
3. Calculate the volume (V) in dm3 of 0.8 mol/dm3 sulphuric acid
that contains 0.2 mol.
Calculation involving concentrations of solutions in mol/dm3

90. leenl@
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Examples
1. 4.0 g of sodium carbonate powder, Na2CO3 is dissolved in
water and made up to 250cm3. What is the molarity of the
solution?
2. Dilute hydrochloric acid has a concentration of 2.0 mol/dm3.
Calculate the mass of hydrogen chloride that is found in
250cm3 of hydrochloric acid?
3. The concentration of a potassium hydroxide solution is 84.0
g/dm3. Calculate the number of moles of potassium hydroxide
present in 300cm3 of the solution.
4. Calculate the number of moles of hydrogen ions present in
200cm3 of 0.5 mol/dm3 sulphuric acid.

91. 7.3 Analysing concentration of acids and
alkalis
LEARNING OUTCOME :
 State the meaning of concentration,
 State the meaning of molarity,
 State the relationship between the number of moles with
molarity and volume of a solution,
 Relate pH value with molarity of acid and alkali,
 Solve numerical problems involving molarity of acids and alkalis

92. Preparation of Standard Solution

93. leenl@
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STANDARD SOLUTION
 A solution in which its concentration is accurately
known.
 A solution of known concentration

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How to prepare a STANDARD SOLUTION?
 Steps to prepare a Standard Solution
1. Calculate the mass of solute needed
2. Weigh out the exact mass of solute needed
3. Dissolve the solute in small amount of distilled
water.
4. Transfer the dissolved solute into a suitable
volumetric flask.
5. Add enough water to the required volume

95. leenl@
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 Preparation of standard solution:
Calculate the mass (m g) of the chemical required to
prepare v cm of solution, where v is the volume of the
volumetric flask (standardised flask).
Weigh m g accurately using an electronic balance.
Dissolve m g of the chemical in distilled water in the
volumetric flask.
How to prepare a STANDARD SOLUTION?

96. Activity 7.8
TO PREPARE A STANDARD SOLUTION
Apparatus : Electronic balance, 100cm3 volumetric flask,
filter funnel, dropper and washing bottle
Materials : Sodium hydroxide solid and distilled water

97. 1. Weigh accurately 8.0 g of NaOH
solid in a weighing bottle using an
electronic balance.
2. Transfer the NaOH solid to a small
beaker. Add enough water to
dissolve all the NaOH solid.
3. Transfer the dissolved NaOH using
filter funnel and glass rod into a 100
cm3 volumetric flask.
4. Rinse the small beaker, the weighing
bottle and the filter funnel using
distilled water and transfer the
contents into the volumetric flask.
5. Add distilled water slowly
until water level near the
mark level of the volumetric
flask. Use dropper to add
water drop by drop.
6. Close the volumetric flask
using stopper.
7. Shake the volumetric flask to
mix the solution completely.

98. Preparing 100 cm3 of 1.0 mol/dm3
aqueous sodium hydroxide solution
 Mass of NaOH required to prepare 100cm3 of 1.0 mol/dm3
= [(MV)/1000] x RMM of NaOH
= [(10 x 100)/1000] x (23 + 16 + 1)
= 4 g
 4.0 g of NaOH is weighed accurately
 4.0 g of NaOH is transferred to a small beaker. Distilled water is added to dissolve the
solid NaOH.

99.  NaOH solution is transferred to a 100 cm3 volumetric flask.
 The small beaker, weighing bottle, etc are all rinsed with distilled and are transferred
into volumetric flask.
 Distilled water is then added slowly until the water level is at the level (calibration)
mark of the volumetric flask.
 Volumetric flask is then closed with stopper and is shaken and inverted to get a
homogeneous solution.

100. Preparation of Solution
by Dilution Method

101. Dilution
 A process of diluting a concentrated solution by
adding a solvent such as water to obtain a more
diluted solution.
 When a solution is diluted, the volume of solvent
increases but the number of moles of solute
remains constant.

102. Steps Involved In The Preparation Of A
Standard Solution By Dilution
1. The volume of the stock solution, V1 required is calculated.
2. The required volume of stock solution is pipetted into a
volumetric flask.
3. Enough distilled water is added to the volumetric flask to
the required volume, V2.

103. 7.3 Analysing concentration of acids and
alkalis
LEARNING OUTCOME :
 State the meaning of concentration,
 State the meaning of molarity,
 State the relationship between the number of moles with
molarity and volume of a solution,
 Describe methods for preparing standard solutions,
 Describe the preparation of a solution with a specified
concentration using dilution method,

104. Relationship between pH values and
Molarities of Acids or Alkalis
 The pH value of an acid or an alkali depends on two factors
 The degree of dissociation
 The molarity or concentration
 At the same concentration, the pH value of an acid or an alkali
depends on the degree of dissociation.
 The higher the degree of dissociation of an acid, the lower the pH
value of an acid.
 The higher the degree of dissociation of an alkali, the higher the pH
value of the alkali

105. 90 cm3
distilled water added
Dilution of solution
M1 = Molarity of original solution / mol dm-3
V1 = Volume of original solution / cm3
M2 = Molarity of the diluted solution / mol dm-3
V2 = Volume of original solution + volume of water added /cm3
M1V1 = M2V2

106. Neutralisation – Acid Base Titration
Pink
Colourless
Alkali
+ phenolphthalein
Acid
Acid + Alkali → Salt + Water
End point – the point during titration at which the indicators changes colour.
Common Indicator
alkalis acidsneutral
Colour in
Methyl orange
Phenolphthalein
Yellow Orange Red
Pink Colourless Colourless

107. Acid-base Titration

108. BALANCE THE NEUTRALISATION
REACTION BELOW ?????
 HNO3 + Ca(OH)2 → Ca(NO3)2 + H2O
 H2SO4 + Ba(OH)2 → BaSO4 + H2O
 CH3COOH + KOH → CH3COOK + H2O
 H3PO4 + NH3 → (NH4)3PO4 + H2O

109. DO YOU KNOW THAT
NEUTRALISATION IS USED IN OUR
DAILY LIFE ???

110. 1. Agriculture : acidic soil is treated with CaO
2. Industries : ammonia is used to prevent coagulation of latex
3. Health :Baking powder to cure bee stings
Toothpaste to neutralise acid in the mouth
NEUTRALISATION IN DAILY LIFE :