Module 1 PPT PDF.pdf of environmental and

UNIT 1-Water
Analysis, Treatment, and Industrial
Application
SAGAR INSTITUTE OF SCIENCE &
TECHNOLOGY GANDHINAGAR, BHOPAL
DR.NEELESH SHRIVASTAVA
PROFESSOR
CHEMISTRY, SISTec, GANDHINAGAR, BHOPAL

BT101 Engineering Chemistry 3L-0T-2P 4 Credits
RAJIV GANDHI PROUDYOGIKI VISHWAVIDYALAYA, BHOPAL
New Scheme Based On AICTE Flexible Curricula
B.Tech. First Year
Branch- Common to All Disciplines
Course Contents:
(i) Water – Analysis, Treatments and Industrial Applications
Sources, Impurities, Hardness & its units, Determination of hardness by EDTA method,
Alkalinity & It’s determination and related numerical problems.
(ii)Boiler problem & softening methods
Boiler troubles (Sludge & Scale, Priming & Foaming, Boiler Corrosion, Caustic
Embrittlement),Softening methods (Lime-Soda, Zeolite and Ion Exchange Methods) and
related numerical problems.
iii) Lubricants and Lubrication
Introduction, Mechanism of lubrication, Classification of lubricants, significance &
determination of Viscosity and Viscosity Index, Flash & Fire Points, Cloud & Pour Points,
Aniline Point, Acid Number, Saponification Number, Steam Emulsification Number and
related numerical problems.

(iv) Polymer & polymerization
Introduction, types of polymerization, Classification, mechanism of polymerization (Free
radical & Ionic polymerization). Thermoplastic &Thermosetting polymers Elementary idea of
Biodegradable polymers, preparation, properties & uses of the following polymers- PVC,
PMMA, Teflon, Nylon 6, Nylon 6:6, Polyester phenol formaldehyde, Urea- Formaldehyde,
Buna N, Buna S, Vulcanization of Rubber.
(v) Phase equilibrium and Corrosion
Phase diagram of single component system (Water) Phase diagram of binary Eutectic System (
Cu-Ag.) Corrosion: Types, Mechanisms & prevention.
(vi) Spectroscopic techniques and application
Principle, Instrumentation & Applications, electronics spectroscopy, Vibrational & Rotational
Spectroscopy of diatomic molecules.
(vii) Periodic properties
Effective Nuclear Charge, Variations: S, P, d & f Orbital energies of atoms in periodic table,
Electronics Configuration, atomic & Ionic sizes, electron affinity & electro negativity, Polari
ability & Oxidation States.

ENGINEERING CHEMISTRY
SUBJECT CODE : BT101
LEARNING OBJECTIVES
❑ INTRODUCTION
❑ SOURCES
❑ IMPURITIES
❑ HARDNESS AND ITS UNITS
❑ DETERMINATION OF HARDNESS BY EDTA METHOD
❑ ALKALINITY, ITS TYPE AND DETERMINATION

INTRODUCTION :-
INTRODUCTION
1. Pure water is very essential for the existence of all living beings (humans,
animals or plants ) without water we can’t survive .
2. Water is an universal solvent.
3. Water is the most useful, wonderful and abundant compound .
4. Only less than 1% of world`s water resources are available for use which is
not sufficient so we have to use available water more carefully and
economically.
5. Water is the important constituents of all the body fluids, without which all
the cells or constituents are in crystalline and dead state;(Human body contains
70% of water).
6. Water is used in almost all human activities, Domestic, Industrial,
Agricultural demand water.

Sources of Water
A) Surface Waters
Rainwater - Pure but contaminated with gases
River Water - High dissolved salts moderate organics
Lake Water - High organics substances
Sea Water - High salinity, pathogens, organics
B) Underground Waters
Spring/Well Water - Crystal clear but high dissolved salts and high
purity from organics

IMPURITIES IN WATER
The following type of impurities are present in water
1.Suspended impurities: Theses impurities impart turbidity, colour and
odour to water. It may be inorganic (clay and sand) or organic (oil
globules, vegetables and animal matter) in nature.
Turbidity: It is due to extremely fine material such as clay finely divided
(organic and inorganic matter).Turbidity expresses the property of water
containing into substance which is insoluble. Substance that scatter light
rather than to transmit in straight line, but turbidity depend not only or
the quantity of soluble substance, but also on size and shape index.
Turbidity in water can be removed by filtration method.
2.Colloidal impurities: Products from organic waste, finely divided
silica and clay etc. are colloidal impurities.

3. Microorganism: They include algae, pathogenic bacteria, viruses,
fungi or fungus and different living beings present in water produces
biological impurities. Many micro organism make water unfit for human
consumption. They cause various diseases. These disease-producing
micro-organism are introduced in to water by animal waste, vegetable
waste or discharge of household, sewage waste, excreta (from animals and
human beings) through sewage flowing in to the river.
4.Dissolved impurities: The presence of dissolved salts like carbonates,
bicarbonates, chlorides and sulphates of calcium, magnesium, iron and
sodium make water hard. Dissolved gases like O2 and CO2 are also
dissolved impurities

Sources of Impurities in water
The following are the sources of impurities in water:
a) Gases: O2 and CO2 are picked up from the atmosphere by rain water.
b) Decomposition of plants and animal residues introduce organic
impurities in water.
c) Water take impurities when it comes in contact with ground, soil or
rocks.
d) Impurities are also introduced in water when it comes in contact with
sewage or industrial waste (Some which are toxic immature release dyes,
paints, insecticides, pesticides detergents, all are chemical wastes which
gets dissolved in water and produces chemical impurities, paper and
pulp industry and textile industry also produces chemical impurities in
water.

Disadvantages of Hard water
Domestic
Washing & Bathing: Hard water does not form lather easily
with soap. As a result, a large amount of soap is wasted.
Drinking: Hard water causes bad effects on our digestive
system. Sometimes, stone formation takes place in kidneys.
Cooking: The boiling point of water is increased due to the
presence of salts. Hence, more fuel and time are required for
cooking.

Industrial:
Textile industry: Hard water causes wastage of soap.
Precipitates of calcium and magnesium soaps adhere to the
fabrics and cause problem.
Paper industry: Calcium and magnesium salts in water may
affect the quality of paper.
Sugar industry: Water containing sulphates, carbonates,
nitrates affects the crystallization sugar.

Dyeing industry: The salts of calcium and magnesium in hard
water react with dyes and spoil the desired shade.
Pharmaceutical industry: Hard water may form some
undesirable products while preparation of pharmaceutical
products.
Concrete making: Chloride and sulphates present in hard
water will affect the hydration of cement and the final strength
of the hardened concrete.
Finally in industries where steam is employed, if hard water is
used in steam production, the troubles like corrosion, scale &
sludge formation, priming & foaming & caustic embrittlement
are seen.

HARDNESS OF WATER
Hardness is the characteristic of water that prevent lathering of
soaps. This is due to the presence of some salts of calcium and
magnesium and other heavy metals dissolved in it .
A sample of hard water is treated with soap (sodium
or potassium salt of higher fatty acid like oleic acid, palmitic
acid, stearic acid) doesn’t produce lather, but on other hand,
forms a white scum or precipitate. This precipitates is formed due
to the presence of insoluble salts of calcium and magnesium in
water.

Following reaction takes place when soap is added to hard
water:

Thus, the water which does not produce lather with soap
solution generally but produces white scum is known as
“Hard water”.
On the other hand, the water which produces lather
with soap is known as “Soft Water”.

Type of Hardness
1. Temporary or Carbonate Hardness or alkaline hardness
2. Permanent Hardness or non-carbonate Hardness or non-
alkaline hardness

Temporary Hardness
Temporary hardness is caused by the presence of
dissolved bicarbonates of calcium, magnesium and other
heavy metals and the carbonate of iron.
It is mostly destroyed by boiling of water, when
bicarbonates are decomposed, yielding insoluble
carbonates or hydroxides, which are deposited as a crust at
the bottom of vessel.

Calcium/Magnesium Carbonates thus formed being almost
insoluble, are deposited as a scale at the bottom of vessel,
while carbon dioxide escapes out.
Temporary hardness is also known as carbonate hardness or
alkaline hardness.

Permanent Hardness
Permanent hardness or non-carbonate hardness is due to the
presence of dissolved chlorides and sulphates of calcium,
magnesium, iron and other heavy metals. Hence, the salts
responsible for permanent hardness are:
CaCl2, MgCl2, CaSO4, MgSO4, FeSO4, Al2 (SO4)3 etc.
Unlike temporary hardness, permanent hardness is not
destroyed by boiling.

But it can be removed by softening method:
(i) Lime soda process:
(ii) Zeolite process:
(iii) Ion-exchange process:

Permanent hardness is also known as non-carbonate hardness
or non-alkaline hardness.
The difference between the total hardness and the
alkaline hardness gives the non-alkaline hardness.

Units of Hardness
 Parts Per Million (ppm): It is defined as the number of
parts by weight of calcium carbonate (CaCO3) present per
million 106 parts by weight of water.
i.e. 1 ppm = 1 part of CaCO3 equivalents hardness in 106
parts of water.
 Milligrams Per Litre (mg/L): It is defined as the number
of milligrams of CaCO3 present in one litre of water.
i.e.1 mg/L= 1 mg of CaCO3 equivalents per litre of water. It
can easily proved that for water.
1 mg/L= 1ppm

Assuming unit density (=mass/volume) for water,
Therefore, 1L=1Kg = 106 mg
1 mg of CaCO3 equivalent per litre of water
1 mg of CaCO3 equivalent hardness per 106 mg of water.
=1 part of CaCO3 per in 106 parts of water= 1 ppm
Hence, 1 mg/L=1 ppm
Degree Clarke (o Cl): It is defined as the number of parts of
CaCO3 equivalent hardness per 70,000 parts of water.
i.e. o Cl = 1 part of CaCO3 per 70,000 parts of water.

 Degree French (o Fr): It is defined as the number of parts of
CaCO3 equivalent hardness per 105 parts of water.
 i.e. o Fr = 1 parts of CaCO3 equivalents hardness per 105
parts of water.
Relationship between various Units of Hardness
As, 1ppm = 1 part per 106 parts of water.
1o Fr = 1 part per 105 parts of water
and 1o Cl= 1 part per 70,000 parts of water.
Therefore, 106 ppm =105 oFr =70,000 o Cl.
Hence, 1 ppm= 0.1 oFr = 0.07 o Cl = 1mg/L.

Calculation of multiplication factor of some salts
Constituents
salts/ion
Molar
mass
n-factor Chemical equivalent
=Molar mass /n-factor
Multiplication factor for
converting into
equivalents of CaCO3
Ca(HCO3)2 162 2 162/2=81 100/(2×81)=100/162
Mg(HCO3)2 146 2 146/2=73 100/(2×73)=100/146
CaSO4 136 2 136/2=68 100/(2×68)=100/136
MgSO4 120 2 120/2=60 100/(2×60)=100/120
CaCl2 111 2 111/2=55.5 100/2×55.5=100/111
CaCl2 95 2 95/2=47.5 100/2×47.5=100/95
CaCO3 100 2 100/2=50 100/2×50=100/100
MgCO3 84 2 84/2=42 100/2×42=100/84
CO2 44 2 44/2=22 100/2×22=100/44
Mg(NO3)2 148 2 148/2=74 100/2×74=100/148
HCO3
- 61 1 61/1=61 100/2×61=100/122
OH- 17 1 17/1=17 100/2×17=100/34
CO3
2- 60 2 60/2=30 100/2×30=100/60
Na AlO2 82 1 82/1=82 100/2×82=100/164
Al2 (SO4)3 342 6 342/6=57 100/2×57=100/114
FeSO4. 7H2O 278 2 278/2=139 100/2×139=100/278
H+ 1 1 1/1=1 100/2×1=100/2

Estimation of Hardness by EDTA
Method
The hardness of water is estimated by EDTA method using
Eriochrome Black–T [EBT] as indicator.
Water hardness is generally caused by the presence of Ca ions and
Mg ions in water. Some other polyvalent ions like strontium, iron,
aluminium, zinc and manganese also contribute to hardness. But
because of their low concentration in natural water, hardness is
generally measured as concentration of only calcium and
magnesium ions.
The estimation of water hardness is done by complexometric
titration using standard EDTA as titrant and EBT as an indicator

The full form of EDTA is Ethylene Di amine Tetra
acetic acid.

Eriochrome Black T (EBT)
Eriochrome Black T is a complexometric indicator that is used
in complexometric titrations, e.g. in the water hardness determination
process. It is an azo compound, carcinogenic in nature. It is mainly
used as an indicator in complexometric titrations for the determination
of total hardness of water due to elements like calcium, zinc, magnesium
and other metal ions. It is well known for its chelating properties.
Sodium 1-[1-Hydroxynaphthylazo]-6-nitro-2-naphthol-4-sulfonate

Principle of EDTA Titrations
The quick, complete and 1:1 interaction of metal ion with EDTA
leading to the formation of stable complex is the basis of
complexometric titrations.
THEORY
The hard water is buffered to a pH value of 10 using NH4OH–
NH4Cl buffer and a few drops of EBT indicator solution are
added. EBT forms a weak complex with metal ions, which has a
wine red colour{reaction (i)}
In the course of the titration of water sample against EDTA,EDTA
first combines with free Ca ions or Mg ions to give very stable,
colourless and water soluble metal–EDTA complex {reaction
ii}.After all the free metal ions are consumed, the next drop of
added EDTA solution displaces the indicator, EBT, from metal-
EBT complex{reaction (iii)}.

 Thus, at the equivalent point ,there is change in colour from
wine red (due to Metal -EBT) to blue (due to free EBT), the
total hardness is thus determined.
 For the determination of permanent hardness, temporary
hardness is first removed by boiling. After the removal of
precipitate by filtration, the permanent hardness in the filtrate
is determined by titration with EDTA as before. Temporary
hardness is then determined by subtracting permanent hardness
from total hardness.

ROLE OF NH4 OH –NH4 Cl BUFFER SOLUTION IN
DETERMINATION OF HARDNESS OF WATER BY
EDTA
 Following important reactions requires basic medium ( pH =10 ),maintained bt
the addition of NH4 OH –NH4 Cl buffer.
 a) Wine red coloured metal eriochrome black-T unstable complex formation, as
per reaction (i).
 b) Colourless metal-EDTA stable complex formation, as per reaction(ii).

 c) Displacement of blue coloured free eriochrome black-T indicator, as per
reaction(iii).

PROCEDURE
(i) Standardization of EDTA Solution: Fill up the burette with EDTA solution after
washing and rinsing. Pipette out,50 mL of standard hard water prepared in such a way that 1
mL of it contains 1 mg of CaCO3 into a 250 mL conical flask. Add 10 mL of buffer solution
and 2-3 drops of indicator (EBT).Titrate this solution against EDTA until the wine-red colour
(due to M-EBT complex) changes to blue (due to EBT).
Let the volume of EDTA consumed be V1 mL.
(ii) Determination of total hardness of water: As per the same procedure given above, titrate
50mL of unknown water sample against EDTA. Let the volume of EDTA consumed this time
be V2 mL.
(iii) Determination of permanent hardness of water: Take 250mL of the water sample in a
500 mL beaker and boil it till the volume is reduced to about 50 mL.This step causes all the
bicarbonates to decompose respectively into insoluble CaCO3 and Mg(OH)2.Filter and wash
the ppt with distilled water and quantitatively collect the filtrate and washings in a 250 mL
conical flask and make up the volume to 250mL with distilled water. Titrate 50 mL of this
water sample against EDTA as in step(i).Let the volume used be V3 mL.

Calculations
Step (i) Standardization of EDTA Solution:
V1 mL of EDTA = 50 mL of standard hard water.
Since, each mL of standard hard water contains 1 mg of CaCO3,
Hence,V1 mL of EDTA= 50 mg of CaCO3
1 mL of EDTA = 50/V1 mg of CaCO3 equivalent hardness.
Step(ii) Determination of total hardness of water:
50 mL of unknown hard water sample= V2 mL of EDTA
= V2*50/V1 mg of CaCO3 equivalent
Therefore, 1,000 mL (or 1L) of unknown hard water sample
= V2 ×50/V1×1/50×1000
= 1000 V2/V1 mg of equivalent hardness
Hence, total hardness CaCO3 of water =1000 × V2 / V1 mg/L
or Total hardness of water =1000 × V2 / V1 mg/L

Step (iii) Determination of permanent hardness of water:
As, 50 mL of boiled water = V3 mL of EDTA
= V3*50/V1 mg of CaCO3 equivalent
Therefore, 1,000 mL (or 1L) of boiled water
= V3*50/V1*1/50*1000= 1000 V3/V1 mg
Hence, permanent hardness of water =1000*V3/V1 mg/L
or Permanent hardness of water =1000*V3/V1 ppm.
Step (iv) Determination of temporary hardness of water:
Since, Temporary hardness = Total hardness –Permanent hardness
= 1000 V2/V1 - 1000*V3/V1
Or ,Temporary hardness = 1000 V2-V3/V1 ppm

NUMERICAL PROBLEMS BASED
ON EDTA

0.28 g of CaCO3 was dissolved in HCL and the solution was made to
one litre with distilled water.100ml of the above solution required 28ml
of EDTA solution on titration.100 ml of the hard water sample required
35 ml of the same EDTA solution on titration. After boiling 100 ml of
this water, cooling, filtering and then titration required 10 ml of EDTA
solution. Calculate the temporary and permanent hardness of water.
Solution:
Step (i) Standardization of EDTA Solution:
Given 1L of standard hard water contains 0.28gm CaCO3 .
Hence, each mL of standard hard water contains 0.28 mg CaCO3
V1 mL of EDTA = 50 mL of standard hard water
As, 28mL of EDTA=100mL of standard hard water
=100× 0.28= 28mg CaCO3
Since 1mL of EDTA = 28/28=1mg CaCO3

Step(ii) Determination of total hardness of water:
100 mL of unknown hard water sample= 35 (V2 ) mL of EDTA
= 35 × 1= 35mg of CaCO3 …….[by using equation (i)]
Therefore, 1,000 mL (or 1L) of unknown hard water sample
=35/100 × 1000= 350 mg of CaCO3 eq. hardness
Hence, Total hardness =350ppm
Step (iii) Determination of permanent hardness of water:
As, 100 mL of boiled water = 10 (V3) mL of EDTA
= 10 ×1= 10mg of CaCO3 equivalent hardness
Therefore, 1,000 mL (or 1L) of boiled water
= 10/100×1000 =100mg of CaCO3 equivalent hardness
Hence, permanent hardness of water =100 ppm
Step (iv) Determination of permanent hardness of water:
Temporary hardness=Total hardness–Permanent hardness
=350-100=250 ppm
Temporary hardness= 250ppm

Alkalinity
Alkalinity of water we mean the total content of those substances in it
which causes an increased hydroxide ion [OH-] upon dissociation or due
to hydrolysis. Alkalinity is a measure of the ability of water to neutralize
the acids.
The alkalinity of water is attributed to the presence of the :
(i)Caustic alkalinity (due to OH- and CO3
2- ions)
(ii) Temporary hardness (due to HCO3
-)
With respect to the constituents causing alkalinity in water, the following
situation may arise:
1.Hydroxide (OH- )only
2.Carbonate (CO3
2- )only
3.Bicarbonate (HCO3
-) only

4.Hydroxide (OH-) and Carbonate (CO3
2- ) together.
5.Carbonate (CO3
2- ) and Bicarbonate (HCO3
-) together.
Note :Why is alkalinity of water cannot be due to simultaneous
presence of OH- , CO3
2- , HCO3
- ?
The possibility of OH- and HCO3
- together is ruled out because
of the fact that they combine instantaneously to form CO3
2-
ions.
Thus, OH- and HCO3
- ions cannot exist together in water. On the
basis of same reasoning, all the three (OH- , CO3
2- , HCO3
- )
cannot exist together

The alkalinity due hydroxide and carbonate can be detected by
Phenolphthalein indicator and so they are collectively called as
Phenolphthalein Alkalinity , represented by P.
The alkalinity due to hydroxide, carbonate and bicarbonate can be
detected by Methyl orange indicator and so it is called as in Methyl
orange Alkalinity, represented by M.

Determination of Alkalinity
Determination of Phenolphthalein Alkalinity, P :
100 ml of given water sample is taken in the conical flask , a few drops of
Phenolphthalein indicated are added and titrated against N/50 H2SO4 ; let
the titre value when the solution becomes colourless, be V1.
Determination of Methyl orange Alkalinity, M :
In the same solution a few drops of Methyl orange indicator are added
and titrated against the same acid until the colour changes from yellow to
red; let the titre value be X .
So, M = V1 + X = V2

Types and Extent of Alkalinity due to
various anions

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