Water Analysis B.tech

1. ENGINEERING CHEMISTRY
(BT-101)
SYLLABUS
UNIT 1 : Water Analysis, Treatments and
Industrial Applications
UNIT 2 : Boiler Problems and Softening
Methods
UNIT 3 : Lubricants and Lubrication
UNIT 4 : Polymers and Polymerization
UNIT 5 : Phase Equilibrium and Corrosion
UNIT 6: Spectroscopic Techniques and
Applications
UNIT 7: Periodic Properties

2. UNIT 1 Water Analysis, Treatments
and Industrial Applications
SOURCES OF WATER
SURFACE WATER Sea RAIN WATER UNDERGROUND WATER
FLOWING
WATER
STILL
WATER
SPRINGS WELLS TUBE-
WELLS
Streams
Rivers
Ponds
Lakes
Reserviors

3. Source of
Water
Inorganic
Impurities
Organic
impurities
Microorganisms
River water Mod Mod Mod
Lake water Min Max Max
Ground water Max Min Min

5. Evaporation
The vapor rises
Condensation
The Clouds form
Precipitation
The rain falls
Transpiration
The movement through plants

6. Ground Water

7. As an engineering tool water is mainly used
for steam generation and it is also used as
a coolant although different uses of water
demand different specifications.
Water is often called the universal solvent.
It dissolves polar compounds through
dipole-dipole interactions. Compounds
with oxygen and nitrogen groups are
Stabilized and solvated through hydrogen-
bonding interactions. This is particularly
important for alcohols, amines, and amides.

8. Coordination of water molecules around the anion and
the cation greatly reduces the ion-ion attraction in the salt.
Water has a very high dielectric constant (80) and
this allows salts to dissolve in water with dissociation.
The dielectric constant tells us how well the solvent is
able to separate ions. The dielectric constant can be
defined as the ratio of the absolute permittivity of a
substance to the absolute permittivity of free space.
Generally, substances with high dielectric constants
break down more easily when subjected to intense
electric fields.

9. IMPURITIES OF WATER
Impurities present in Water can be
categorized as;
• Physical may be Suspended or Colloidal
(Physical parameters are colour, taste, odour, density, turbidity, TDS, thermal properties, etc.)
• Chemical like Dissolved gases, Dissolved
organic Salts, Dissolved inorganic Salts
(Chemical parameters are conductivity, alkalinity, hardness, ions, heavy metals, DO, COD, pH, etc.)
• Biological like Bacteria, Fungi, Algae
(Biological parameters are MPN, BOD etc.)

10. SOURSES OF IMPURITIES
• Soil
• Sewage
• Domestic and industrial waste
• Organic impurities
• Rain

11. EFFECTS OF IMPURITIES
• Odour
• Turbidity
• Taste :Bitter, Soapy, Brackish, Palatable
• Colour :Yellow, Yellow red, Red brown
• PH
• Temperature
• Nature : a) Pathogenic b) Hardness

12. TYPES OF WATER
HARD WATER SOFT WATER
HARDNESS
Soap consuming property of water

13. Hardness of Water:
Hardness is defined as soap consuming capacity of water sample.
It is that characteristic “which prevent the lathering of soap.” It is
due to presence of certain salts of Ca, Mg and other heavy metal
ions like Al3+, Fe3+ and Mn2+ dissolved in water. A sample of
hard water, when treated with soap (K or Na salt of higher fatty
acids like oleic, palmitic or stearic acid), does not produce lather,
but forms insoluble white scum or ppt of calcium and magnesium
soaps.
C17H35COONa + H2O C17H35COOH
C17H35COOH + C17H35COONa  LATHER
2C17H35COONa +CaCl2  (C17H35COO)2Ca + 2 NaCl.
Soap (Hardness) Calcium Sterate
(Sodium Sterate) (Insoluble)
2C17 H35 COO Na + MgSO4 → (C17 H35 COO)2 Mg + Na2SO4
Soap (Hardness) Magnesium Sterate (Insoluble)

14. When you rub a bar soap over your wet skin, washcloth or scrubby you create friction. This
friction introduces tiny air bubbles onto the surface of the wet soap.
The hydrophobic (water repelling) end does not like the wet, watery soap and wants to
leave, so it attaches itself to the nearest air bubble. Soon the air bubbles are covered in the
hydrophobic ends of the soap molecules. This creates a thin film that encloses a tiny bit of
air and that forms a soap bubble.

15. Hardness
TEMPORARY/ ALKALINE/ CARBONATE
HARDNESS
PERMANENT/ NON ALKALINE/ NON
CARBONATE HARDNESS
Ca(HCO3)2  CaCO3 + H2O + CO2
Mg (HCO3)2  Mg (OH)2 + 2CO2
CO3- - and HCO3- of Ca++/ Mg++/ Fe++ and
Other heavy metals
Cl - and SO4- - of Ca++/ Mg++/ Fe++ and
Other heavy metals

16. PRESENTATION : In terms of CaCO3 equivalents
Molecular weight is 100 and eq. weight is 50
Most insoluble salt in water

17. CaCO3 equivalent=
(ppm)
Mass of substance X Multiplication Factor
Mass of substance X
Eq. wt. of CaCO3
Eq. wt. of
substance

18. Constituent Salt
/ ion
Molar
Mass (a)
n factor (b)
Chemical
equivalent=(a)/(b)
Multiplication factor for
converting into equivalents
of CaCO3
Ca (HCO3)2 162 2 (divalent) 162/2 = 81 100/2 x 81 = 100/162
Mg (HCO3)2 146 2 146/2 = 73 100/2 x 73 = 100/146
CaSO4 136 2 136/2 = 68 100/2 x 68 = 100/136
MgSO4 120 2 120/2 = 60 100/2 x 60 = 100/120
CaCl2 111 2 111/2 = 47.5 100/2 x 47.5 = 100/111
MgCl2 95 2 95/2 = 47.5 100/2 x 50 = 100/95
CaCO3 100 2 100/2 = 50 100/2 x 50 = 100/100
MgCO3 84 2 84/2 = 42 100/2 x 42 = 100/84
CO2 44 2 44/2 = 22 100/2 x 22 = 100/44
Mg (NO3)2 148 2 148/2 = 74 100/2 x 74 = 100/148
Multiplication factors for different salts are:

19. HCO3 61
1
(monovalent
)
61/1 = 61 100/2 x 61 = 100/122
OH- 17 1 17/1 = 17 100/2 x 17 = 100/34
CO3
2 - 60 2 60/2 = 30 100/2 x 30 = 100/60
NaAlO2 82 1 82/2 = 82 82/2 x 82 = 100/164
Al2 (SO4)3 342 6 342/6 = 57 100/2 x 57 = 100/114
FeSO4 . 7H2O 278 2 278/2 = 139 100/2 x 139 = 100/278
H+ 1 1 1/1 = 1 100/2 x 1 = 100/2
Multiplication factors for different salts are:

20. UNITS OF HARDNESS
ppm
mg/L
Degree Clark (o Cl)/ Grains per gallon
Degree French (o Fr)
1ppm = 1mg/L = 0.07 o Cl = 1 o Fr

21. Requirements:
Apparatus Required: Burette, pipette, conical flask,
beaker, dropper, etc.
Chemicals Required: EDTA, water sample,
Eriochrome Black-T, buffer solution of NH4Cl & NH4OH
DETERMINATION OF HARDNESS BY
EDTA/ COMPLEXOMETRIC METHOD

22. Theory:
As EDTA is a chelating agent, hence Ca++ and Mg++ ions
form a complex with EDTA and at the end point all the Ca++
and Mg++ ions present in the water sample converted to
Ca-EDTA and Mg-EDTA complex.
I) M++ + [EBT] at 10 pH [M-EBT]
Hard water Wine red,
M++ = Ca++ or Mg++ Unstable complex
II) [M-EBT] + [Na2EDTA] [M-EDTA] + [EBT] + 2Na+
Colorless, soluble Blue
Stable complex

23. Funnel

24. Pipette
Conical Flask

25. Chemical Reactions involved in complexometric titration:
Hard Water
EBT/ Eriochrome black T/ Solochrome black
[ M-EBT ]

26. Blue
M-EDTA Stable, Colourless, Soluble complex
Wine red unstable complex
Divalent anion of EDTA

27. Procedure:
1)Burette is filled with standard EDTA solution.
2)Hard water is pipette out in a conical flask.
3)2 ml of buffer solution and then 1-2 drops of
Eriochrome Black-T are added into it, the
solution becomes wine red in color.
4)The solution is titrated with EDTA solution till the
color changes to sky blue.
5)The volume of EDTA solution consumed is noted
and same experiment is repeated to get
concordant reading.

28. Observation Table:
S.
No.
Vol of hard
water (ml)
Burette
reading
Initial
(ml)
Burette
reading
Final (ml)
Vol of
EDTA
Solution
used (ml)
1 10 o.o V1
2 10 o.o V2 V2
3 10 0.0 V2

29. Calculation:
Hardness = ENV X 1000 mg/L
Vol of water sample
E = Eq. Wt. of CaCO3
N = Normality of EDTA solution
V = Vol of EDTA used

30. Result: The total hardness present in the given
water sample is ………….ppm.
Precautions:
1)Burette and pipette should be rinsed before
experiment.
2)Burette should be filled up to zero mark.
3)Air bubbles should be removed from burette.
4)Last drop from pipette should not be transferred
into conical flask.
5)End point should be noted carefully.

31. Calulation steps for numericals : DETERMINATION OF
HARDNESS BY EDTA/ COMPLEXOMETRIC METHOD
using Standard Hard Water
Requirements:
Apparatus Required: Burette, pipette, conical
flask, beaker, dropper, etc.
Chemicals Required: EDTA, water sample,
standard hard water, eriochrome Black-T,
buffer solution of NH4Cl & NH4OH

32. Procedure:
1)Burette is filled with EDTA solution.
2)Standard hard water is pipette out in a conical
flask.
3)2 ml of buffer solution and then 1-2 drops of
Eriochrome Black-T are added into it, the
solution becomes wine red in color.
4)The solution is titrated with EDTA solution till the
color changes to sky blue.
5)The volume of EDTA solution consumed is noted
and same experiment is repeated to get
concordant reading.
6)The same experiment is repeated with water
sample and then boiled water sample.

33. Observation Table:
S.
No.
Vol of hard
water (ml)
Burette
reading
Initial
(ml)
Burette
reading
Final (ml)
Vol of
EDTA
Solution
used (ml)
1 10 o.o
2 10 o.o V2
3 10 0.0
(I) For standard hard water (SHW)

34. Observation Table:
S.
No.
Vol of hard
water (ml)
Burette
reading
Initial
(ml)
Burette
reading
Final (ml)
Vol of
EDTA
Solution
used (ml)
1 10 o.o
2 10 o.o V2’
3 10 0.0
(II) For water sample (WS)

35. Observation Table:
S.
No.
Vol of hard
water (ml)
Burette
reading
Initial
(ml)
Burette
reading
Final (ml)
Vol of
EDTA
Solution
used (ml)
1 10 o.o
2 10 o.o V2’’
3 10 0.0
(III) For boiled water sample (WS)

36. Calculation:
Strength of Standard Hard Water (SHW) = x gm/L
Strength = Normality X equivalent
So Normality of SHW (N1) = x/50
NV = Constant
(I) N1V1 (SHW) = N2V2 (EDTA)
(II) N3V3 (HW) = N2V2’ (EDTA)
Total Hardness = N3 X 50 X 1000 mg/L
(III) N4V4 (HW after boiling) = N2V2’’ (EDTA)
Permanent Hardness = N4 X 50 X 1000 mg/L
Temporary Hardness = Tot. Hard.- Perma. Hard.