ENGINEERING CHEMISTRY LAB MANUAL - sitams.org

SREENIVASA INSTITUTE OF TECHNOLOGY AND MANAGEMENT STUDIES-CHITTOOR

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ENGINEERING CHEMISTRY

LAB MANUAL

INSTITUTE VISION AND MISSION

Vision To ensure as a centre of excellence for learning and research in the domains of

engineering, computing and management.

Mission

Provide congenial academic ambience with state – ate of resources for learning and

research.

Ignite the students to acquire self- reliance in the latest technologies

Unlease and encourage the innate potential and creativity of students.

Inculcate confidence to face and experience new challenges.

Foster enterprising spirit among students.

Work collaboratively with technical institutes/ universities/industries of national and

international repute


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PROGRAM OUTCOMES (PO’s) PO1. Engineering knowledge: Apply the knowledge of mathematics, science, engineering

fundamentals and an engineering specialization to the solution of complex engineering problems.

PO2. Problem analysis: Identify, formulate, review research literature and analyze complex

engineering problems reaching substantiated conclusions using first principles of mathematics,

natural sciences and engineering sciences.

PO3. Design/development of solutions: Design solutions for complex engineering problems and

design system components or processes that meet the specified needs with appropriate

consideration for the public health and safety and the cultural, societal and environmental

considerations.

PO4. Conduct investigations of complex problems: Use research-based knowledge and research

methods including design of experiments, analysis and interpretation of data and synthesis of the

information to provide valid conclusions.

PO5. Modern tool usage: Create, select and apply appropriate techniques, resources and modern

engineering and IT tools including prediction and modeling to complex engineering activities with

an understanding of the limitations.

PO6. The engineer and society: Apply reasoning informed by the contextual knowledge to assess

societal, health, safety, legal and cultural issues and the consequent responsibilities relevant to the

professional engineering practice.

PO7. Environment and sustainability: Understand the impact of the professional engineering

solutions in societal and environmental contexts, and demonstrate the knowledge of and need for

sustainable development.

PO8. Ethics: Apply ethical principles and commit to professional ethics and responsibilities and

norms of the engineering practice.

PO9. Individual and team work: Function effectively as an individual and as a member or leader in

diverse teams and in multidisciplinary settings.

PO10. Communication: Communicate effectively on complex engineering activities with the

engineering community and with society at large, such as, being able to comprehend and write

effective reports and design documentation, make effective presentations and give and receive

clear instructions.

PO11. Project management and finance: Demonstrate knowledge and understanding of the

engineering and management principles and apply these to one’s own work, as a member and

leader in a team, to manage projects and in multidisciplinary environments.

PO12. Life-long learning: Recognize the need for and have the preparation and ability to engage in

independent and life-long learning in the broadest context of technological change.


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LAB COURSE SYLLABUS, LAB COURSE OUTCOMES,

CO Vs PO/PSO MAPPING

ENGINEERING CHEMISTRY LAB

The following Experiments must be done during Semester.

CEO1: To Demonstrate Knowledge on measurement of various analysis of water treatment

methods.

CEO2: To Identify the different salt analysis of copper for engineering and technological

applications.

CEO3: Provide valid conclusions on phenomena of dissolved oxygen

S. No. Name of the Experiment

1. Preparation of Standard EDTA solution and Estimation of Hardness of Water

2. Preparation of Standard EDTA and Estimation of Copper

3. Estimation of dissolved oxygen in given water sample

4. Estimation of alkalinity of water

5. Estimation of Acidity of water sample.

6. Preparation of Standard Potassium Dichromate and Estimation of Ferrous Iron

7. Preparation of Standard Potassium Dichromate and Estimation of Copper by

Iodometry

8. Determination of strength of the given Hydrochloric acid against standard sodium

hydroxide Solution by Conductometric titration

9. Conductometric titration of BaCl2 Vs Na2SO4 (Precipitation Titration).

10 Determination of viscosity of the given oils through Redwood viscometer


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Course Outcomes:

On successful completion of the course the will be able to,

Course Outcomes POs related to

COs

CO1

Demonstrate Knowledge on measurement of various analysis of

water treatment methods PO1

CO2 Identify the different salt analysis of copper for engineering and

technological applications. PO2

CO3 Provide valid conclusions on phenomena of dissolved oxygen. PO4

CO4 Follow ethical values during conducting of alkalinity of water

samples. PO8

CO5 Work individually or in a team effectively. PO9

CO6 Communicate verbally and in written form pertaining to results of

the Experiments. PO10

CO7 Learns to perform experiments involving physical Phenomena in

future years. PO12


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(ENGINEERING CHEMISTRY) LABORATORY MANUAL

__I_ B.TECH __ SEMESTER regulation: 18

Name of Student : Roll Number : Subject Code :

FACULTY INCHARGE: Designation:

DEPARTMENT:


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SITAMS

ENGINEERING CHEMISTRY

LABORATORY Subject Code :18SAH116

INDEX

Sl.

No. Date Name of the Experiment/Exercise

Page

No. Marks Signature

1 Preparation of Standard EDTA solution and

Estimation of Hardness of Water

2 Preparation of Standard EDTA and Estimation of

Copper

3 Estimation of dissolved oxygen in given water sample

4 Estimation of alkalinity of water

5 Estimation of Acidity of water sample

6 Preparation of Standard Potassium Dichromate and

Estimation of Ferrous Iron

7 Preparation of Standard Potassium Dichromate and

Estimation of Copper by Iodometry

8 Determination of strength of the given Hydrochloric

acid against standard sodium hydroxide Solution by

Conductometric titration

9 Conductometric titration of BaCl2 Vs Na2SO4

(Precipitation Titration)

10 Determination of viscosity of the given oils through

Redwood viscometer

Signature of the faculty in-charge with date


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SITAMS

Engineering CHEMISTRY Laboratory Subject Code :18SAH116

INDEX

Sl.

No. Date Name of the Experiment/Exercise

Page

No. Marks Signature

1 Preparation of Standard EDTA solution and

Estimation of Hardness of Water (Demo)

2

3

4

5

6

7

8

9

10

11

12

Signature of the faculty in-charge with date


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Experiment to be mapped against COs & POs/PSOs

PO1 PO2 PO3 PO4 PO5 PO6 PO7 PO8 PO9 PO10 PO11 PO12

CO1 √

CO2 √

CO3 √

CO4 √

CO5 √

CO6 √

CO7 √


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Teachers Lab Manual

(Master Readings-with sample calculations and results for each experiment)


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I. Standardization of EDTA (CaCO3 Vs EDTA)

S.NO Volume of

CaCO3 (Ml)

Burette reading Concordant value (Ml)

Initial (Ml) Final(Ml)

Calculation

Volume of standard CaCO3 (V1) = 20 Ml

Normality of CaCO3 (N1) = …...…… N

Volume of EDTA solution (V2) = …………Ml

Normality of EDTA solution (N2) = ………..

N1V1 = N2V2

N2 =

=

Normality of EDTA solution (N2) =


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EXPERIMENT NO: DATE:

PREPARATION OF STANDARD EDTA SOLUTION AND

ESTIMATION OF HARDNESS OF WATER

Aim:

To determine the total hardness, permanent hardness, and temporary hardness of a

given water sample by EDTA method.

Apparatus:

Conical flask, Standard volumetric flasks, Beakers, Funnels, Filter papers, Burette and

Pipette.

Chemicals required:

EDTA solution, Buffer solution of pH =10, Eriochrome Black – T indicator,

0.01NCaCO3solution.

1) EDTA solution: 4.65 g of EDTA is dissolved in little amount of distilled water and

make up to the mark of 250 Ml with distilled water.

2) Buffer solution of PH

=10: 142 Ml of Con.NH3 solution is added to 17.5 g of NH4Cl

and diluted to 250 Ml with distilled water.

3) Erichrome Black-T indicator: 0.2 g of dye stuff is dissolved in 15 Ml of tri &

Thioline and 5 Ml of absolute ethanol.

4) 0.01N CaCO3solution:727.5mg of CaCO3is accurately weighed and dissolved in

water and diluted to 100 Ml with distilled water.

Principle:

Disodium salt of Ethylenediaminetetraaceticacid (EDTA) is used to determine the

various kind of hardness in the given hard water sample. The hardness causing metal ions

which are calcium and magnesium form a wine red coloured weak complex with Eriochrome

Black – Tindicator in the presence of a basic buffer (pH=10) solution. When EDTA is added,

the indicator is replaced by EDTA and a stable metal complex is formed. From the volume of

EDTA consumed, the hardness can be calculated.


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II. Estimation of total hardness of water sample:

S.NO

Volume of hard

water sample

(Ml)

Burette reading

Concordant value (Ml)


Calculation

Volume of hard water sample V1 = 20 Ml

Normality of water sample N1 = …...…… N

Volume of EDTA solution V2 = …………Ml

Normalityof EDTA solution N2 = ………...N

N1V1 = N2V2.

1

221

V

VNN

=

Total hardness of the hard water sample =N1x 50 x 1000 ppm

=

Total hardness of the hard water sample = …………………ppm


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(Disodium salt of Ethylene di amine tetra acetic acid)

The indicator forms a weak complex with the metal ion present in the hard water and

gives wine red color.

When EDTA is added to the hard water, the metal ions form stable metal complexes

with EDTA by leaving the indicator which give deep blue colour, which denotes the end

point. The metal EDTA complex is stable at pH 8 – 10. This pH range can be maintained by

adding ammonia buffer (NH4Cl + NH4OH).

Procedure

Titration I: Standardization of EDTA

The burette is washed well with the distilled water and then rinsed with a little amount

of the given EDTA solution. It is then filled with the same EDTA solution upto the zero level

without air bubbles. Initial reading of the burette is noted. 20 Ml of standard CaCO3 solution

is pipetted out into a clean conical flask. 5 Ml of ammonia buffer solution and 2 drops of

EBT indicator are added. The solution turns into wine red color and it is titrated against

EDTA taken in the burette. The change of wine red color to deep blue color is the end point.

The final reading in the burette is noted. The difference in the burette reading gives the

volume of EDTA solution. The titration is repeated to get concordant values.

H2C

H2CN N

CH2COOH

CH2COONa

NaOOCH2C

HOOCH2C

Mg2+ + EBT [Mg-EBT]

wine red

[Mg-EBT] + EDTA [Mg-EDTA] + EBTdeep blue

[Ca-EBT] + EDTA [Ca-EDTA] + EBTdeep blue

Ca2+ + EBT [Ca-EBT]

wine red


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III. Estimation of permanent hardness of water sample:

S.NO

Volume of

hard water

sample (Ml)

Burette reading Concordant value

(Ml) Initial (Ml) Final(Ml)

Calculation

Volume of boiled water sample V1 = 20 Ml

Normality of boiledwater sample N1 = …...…… N

Volume of EDTA solution V2 = …………Ml

Normality of EDTA solution N2 = ………....N

N1V1 = N2V2.

1

221

V

VNN

=

Permanent hardness of the hard water sample = N1x50 x 1000 ppm

=

Permanent hardness of the hard water sample = …………………ppm

IV. Estimation of temporary hardness of the hard water

Temporary Hardness = Total Hardness – Permanent Hardness

= ……………….. - .……………….

= …………………..ppm

Temporary hardness of the hard water sample = …………………ppm


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Titration II: Estimation of total hardness of hard water sample

20 Ml of the given hard water sample is pipetted out into a clean conical flask. 5 Ml

of ammonia buffer solution and 2 drops of EBT indicator are added. The solution turns into

wine red color and it is titrated against EDTA taken in the burette. The change of wine red

color to deep blue color is the end point. The final reading in the burette is noted. The

difference in the burette readings gives the volume of EDTA solution. The titration is

repeated to get concordant values.

Titration III: Estimation of permanent hardnessof hard water sample

100 Ml the hard water sample is taken in a beaker and boiled for 10 – 15 minutes. It is

then cooled and filtered. The filtrate is collected in a 100 Ml standard flask. 20 Ml of this

made up solution is pipetted out in to a clean conical flask. 5 Ml of ammonia buffer solution

and 2 drops of EBT indicator are added. The solution turns into wine red color and it is

titrated against EDTA taken in the burette. The change of wine red color to deep blue color is

the end point. The final reading in the burette is noted. The difference in the burette readings

gives the volume of EDTA solution. The titration is repeated to get concordant values.

Result:

The given sample contains

Permanent Hardness = ppm

Temporary Hardness = ppm

Total Hardness = ppm



CO1 √

CO2 √

CO3 √

CO4 √

CO5 √

CO6 √

CO7 √


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Titration I

Standardization of EDTA

Calculation

Volume of Copper Sulphate (V1) = 20 Ml

Normality of Copper Sulphate (N1) = 0.01 N

Volume of EDTA (V2) = Ml

Normality of EDTA (N2) = ?

V1N1 = V2N2

2

112

V

VNN

=

= __________ N

S.NO Volume ofCuSO4

(Ml)

Burette Reading Concordant value (Ml)



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EXPERIMENT NO : DATE:

PREPARATION OF STANDARD EDTA AND ESTIMATION OF

COPPER

Aim:

To estimate the amount of copper ion present in 100 Ml of given solution using

standard EDTA solution.

Apparatus:

Burette, Pipette, Conical flask, Funnel, Standard flask.

Principle:

Ethylenediamine tetra acetic acid forms a stable complex with Cu+2

ions. This

reaction takes place in presence of basic buffer of pH 10. The completion of the reaction is

noted by the appearance of blue colour, at the end point which is appeared using Fast sulfone

black - F indicator.

1 mole of CuSO4 = 1 mole of EDTA.

Procedure:

Titration I: Standardization of EDTA

The burette is initially washed with distilled water and rinsed with EDTA solution

then filled with the same solution from zero mark to nozzle without any air bubbles. Then

20Ml of standard CuSO4 solution is pipette out into a clean conical flask and one or two

drops of Fast sulfone black - F indicator and 5 Ml of buffer (ammonical buffer) is added in to

the conical flask solution. The colour of solution turns into blue colour. This solution is

titrated against standard EDTA till blue colour changed to green, which is the end point of the

titration. The burette reading is noted. The titration is repeated until two concurrent values are

obtained. The molarity of CuSO4 solution is calculated and the weight of Cu2+

ions present in

the given solution is calculated

Cu2+ + EDTA [Cu-EDTA]

Green


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Titration II

Standard EDTA Vs CuSO4

Calculation

Volume of EDTA (V1) = Ml

Normality of EDTA (N1) = N

Volume of Copper Sulphate (V2) = 20 Ml

Normality of Copper Sulphate (N2) = ?

V1N1 = V2N2

2

112

V

VNN

=

= __________ N

Weight Cu+2

ions present in the given 100 Ml of the solution =10

54.633 M

=

The amount of Cu+2

ions present in given 100 Ml of solution = ______________ g

S.NO Volume ofCuSO4

(Ml)

Burette Reading Concordant value (Ml)



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Titration II: Estimation of copper ions in given solution

The sample solution given in the standard flask is made up to mark using distilled

water. 20Ml of this solution is pippetted out into a clean conical flask. About 5Ml of

ammonia buffer solution and a drop of Fast Sulphone Black-F indicator is added to the

solution. The colour of solution turns into blue colour. This solution is titrated against

standard EDTA till blue colour changed to green, which is the end point of the titration. The

burette reading is noted. The titration is repeated until two concurrent values are obtained.

The molarity of CuSO4 solution is calculated and the weight of Cu2+

ions present in the given

solution is calculated.

Result:

The amount of Cu+2

ions present in given 100 Ml of CuSO4 solution = ____________ g



CO1 √

CO2 √

CO3 √

CO4 √

CO5 √

CO6 √

CO7 √


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Titration I

Estimation of Dissolved Oxygen in tap water(Tap water Vs Sodium thiosulphate)

S.NO Volume of Water

sample (Ml)

Burette Reading



1

2

3

4

5

Calculation

Volume of sodium thiosulphate (V1) = _______Ml

Normality of Sodium thiosulphate (N1) = 0.001 N

Volume of water sample (V2) = 20 Ml

Normality of water sample (N2) = ?

V1N1= V2N2

2

112

V

VNN

=

= __________ N

Dissolved oxygen in tap water = N2 x 8 x 1000mg/L

=

The amount of dissolved oxygen present in tap water = __________ mg/L


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ESTIMATION OF DISSOLVED OXYGEN IN GIVEN WATER SAMPLE

Aim:

To determine the amount of dissolved oxygen present in the given water sample by

Winkler’s method.

Apparatus:

Burette, Pipette, Conical flasks, Funnel, Reagent bottles.

Chemicals:

MnSO4, KOH, KI, H2SO4, Hypo and Starch.

Principle:

This method is based on the fact that D.O oxidizes Mn2+

to higher Oxidation state.

The oxidized manganese is then made to liberate iodide ion from potassium iodide. The

amount of iodine liberated is equivalent to the dissolved oxygen originally present. The

iodine liberated is estimated by titrating with sodium thiosulphate solution.


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Titration II

Estimation of Dissolved Oxygen in distilled water

Distilled water Vs Sodium thiosulphate

S.NO Volume of water

sample (Ml)

Burette reading

Concordant value(Ml)


1

2

3

4

5

Calculation

Volume of sodium thiosulphate (V1) = _______Ml

Normality of sodium thiosulphate (N1) = 0.001 N



V1N1= V2N2

2

112

V

VNN

=

= __________ N

Dissolved oxygen in Distilled water = N2 x 8 x 1000mg/L

=

The amount of dissolved oxygen present in Distilled water = __________ mg/L


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Preparation of Reagents:

1) Saturated sodium thiosulphate solution: To prepare standard 0.001N Hypo

solution, dissolve 0.2482g of Hypo in 1000Ml of distill water.

2) MnSO4 solution: Weigh about 48g of MnSO4 and dissolve it in 100Ml of hot water.

Filter the solution if it is not clear.

3) 10% Alkaline iodide-Azide solution: Dissolve 100g of KOH and 25g of KI in 250

Ml of distilled water. Dissolve 10g sodiumazide and add to the solution.

4) Starch indicator: Prepare fresh solution of starch by dissolving starch powder in hot

water.

Procedure:

Titration I: Estimation of dissolved oxygen in tap water

Tap water sample is taken into a Stoppard BOD bottle. To this, 2Ml of MnSO4 solution

and 2Ml of alkaline iodide solution are added. Stopper is replaced in the reagent bottle and

then shaken well for several times for the uniform mixing of reagents without allowing air to

enter into it. The flask is left aside for some time to form the precipitate. Then 2Ml of Con.

H2SO4 is added and the bottle is shaken gently to dissolve the precipitate.

10 Ml of this solution is pipetted out in to a clean conical flask. Burette is washed with

distilled water and rinsed with hypo solution then it filled with the same solution. The conical

flask sample is titrated against standardized sodium thiosulphate solution. When the solution

becomes light yellow, starch indicator is added and the colour turns to dark bluethen the

titration is continued. The end point is disappearance of blue color.

The titration is repeated to get concordant values. From the titre value the strength of

dissolved oxygen is calculated and hence the amount of dissolved oxygen in the water sample

is calculated.

Titration II: Estimation of dissolved oxygen in distilled water

Reagent bottle is filled with distilled water and the above procedure is repeated with

distilled water then titration is done against hypo solution using starch as indicator.


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Result

(1) The amount of dissolved oxygen present in tap water = __________mg/L



CO1 √

CO2 √

CO3 √

CO4 √

CO5 √

CO6 √

CO7 √


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Estimation of alkalinity of water sample (Water sample Vs Standard HCl)

S. No

Volume of

Water

Sample

(Ml)

Burette reading (Ml) Concordant value (Ml)

Initial

Final

[P]

[M]

At

phenolphthalein

end point [P]

At methyl

orange end

point [M]

Calculation – 1: Phenolphthalein alkalinity.

Volume of HCl (V1) = Ml [P]

Normality of HCl (N1) = 0.01 N



V1N1= V2N2

2

112

V

VNN

Phenolphthalein alkalinity (OH- or CO3

2-) = N2 x 50 X 1000

=

=___________ ppm


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ESTIMATION OF ALKALINITY OF WATER

Aim:

To determine the type and amount of alkalinity present in the given water sample. A

standard hydrochloric acid solution of strength 0.01 N is given.

Principle:

Alkalinity is caused by the presence of hydroxide, carbonate and bicarbonate. There are

five alkalinity conditions possible in a given sample of water, (i). Hydroxide only,(ii.)

Carbonate only, (iii.) Bicarbonate only,(iv.) Combination of carbonate and hydroxide or (v.)

Carbonate and bicarbonate. The various alkalinities can be estimated by titrating with a

standard acid using phenolphthalein and methyl orange indicators.

(i) Phenolphthalein end point

Hydroxide alkalinity is completely neutralized and carbonate alkalinity is partially

neutralized during phenolphthalein end point.

OH- + H+ H2O

CO32- + H+ HCO3

-

(ii) Methyl orange end point

Bicarbonate neutralization occurs during methyl orange end point.

From the two titre values, the different alkalinities are calculated.

When,

P=M Hydroxide alkalinity

2P=M Carbonate alkalinity

P=0 Bicarbonate alkalinity

P<½ M Carbonate and bicarbonate alkalinity

P>½M Hydroxide and carbonate alkalinity

HCO3- + H+ H2CO3


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Alkalinity values are expressed in terms of milligram per liter as calcium carbonate

equivalents.

Calculation – 2: Methyl orange (or) Total alkalinity.

Volume of HCl (V1) = Ml [M]

Normality of HCl (N1) = 0.01 N



V1N1= V2N2

2

112

V

VNN

=

Result of titration

of [P] and [M]

Hardness causing ions

OH- CO3

2- HCO3

-

[P] = 0 0 0 [M]

[P] = [M] [P] or [M] 0 0

[P] = ½[M] 0 2[P] or [M] 0

[P] > ½ [M] 2[P] – [M] 2[M] – 2[P] 0

[P] < ½ [M] 0 2[P] [M] – 2[P]


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Methyl orange (or) Total alkalinity (CO32-

or HCO3-) = N2 x 50 X 1000

=___________ ppm

Result:

1. Phenolphthalein alkalinity---------------- ppm

2. Methyl orange alkalinity---------------- ppm



CO1 √

CO2 √

CO3 √

CO4 √

CO5 √

CO6 √

CO7 √


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Water sample Vs standard NaOH

S. No.

Volume

of water

sample

(mL)

Burette reading (mL) Concordant value

(mL)

Initial

Final

[M] [P] At methyl

orange end

point [M]

At

phenolphthalein

end point [P]

Calculation

i. Mineral acidity

Volume of NaOH (V1)= …………mL [M]

Normality of NaOH (N1) =0.01 N

Volume of water sample (V2) = 20 mL

Strength of water sample (mineral acidity) (N2) = ?

N1V1 = N2V2

N2=

=

N2= …………….N

Mineral acidity = N2 x 50 X 1000 ppm

=

Mineral acidity = ……………...... ppm


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DETERMINATION OF ACIDITY OF WATER

Aim:

To determine the acidity present in the given water sampleby using a standard

solution of NaOH.

Apparatus:

Burette, Pipette, Measuring Jar and Conical flask.

Chemicals:

Standard NaOH solution, methyl orange and phenolphthalein.

Principle:

Acidity of water is its quantitative capacity to react with a strong base to a designated

pH.Different kinds of acidities viz. mineral acidity and total acidity can be estimated by

titrating with a standard NaOH using methyl orange and phenolphthalein indicators. Mineral

acidity can be estimated using methyl orange indicator. The color change is orange red to

yellow. Total acidity is estimated using phenolphthalein indicator by titrating with standard

NaOH until the appearance of pale pink color.

H+ + OH- H2O

Procedure:

Burette is washed with distilled water and rinsed with standard NaOH solution. Then

the burette is filled with the same solution up to the zero mark without any air bubbles.

The water sample is given in standard flask. The volume is made up to 100mL using

distilled water. 20 mL of water sample is measured and transferred into a clean conical flask

then few drops of methyl orange indicator are added to the conical flask. The solution is

titrated againstNaOH solution till the color changes from orange red to yellow(Note: Please

do not throw away this solution, as it is continued further). The volume consumed by water

sample is noted. Then 2 to 3 drops of phenolphthalein indicator is added to the same solution.

The titration is continued till the water sample color is turned to pale pink. The end point is

noted. The titration is repeated until the two concordant values are obtained.


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ii. Total acidity

Volume of NaOH (V1) = …………mL [P]

Normality of NaOH (N1) = 0.01 N

Volume of water sample (V2) = 20 mL

Strength of water sample (total acidity) (N2) = ?

N1V1 = N2V2

N2=

=

N2 = …………….N

Total acidity = N2 x 50 X 1000 ppm

=

Total acidity = ……………...... ppm


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Result:

The given water sample contains

Mineral acidity = ……………...... ppm

Total acidity = ……………...... ppm



CO1 √

CO2 √

CO3 √

CO4 √

CO5 √

CO6 √

CO7 √


(AUTONOMOUS)

33

Titration I

Standardization of K2Cr2O7 (Standard FAS Vs K2Cr2O7)

S.NO Volume of FAS

(Ml)

Burette reading



Calculation

Volume of Ferrous Ammonium Sulphate (V1) = 20 Ml

Normality of Ferrous Ammonium Sulphate (N1) = 0.01 N

Volume of potassium dichromate (V2) = Ml

Normality of potassium dichromate (N2) = ?

V1N1 = V2N2

2

112

V

VNN

=

= __________ N


(AUTONOMOUS)

34


PREPARATION OF STANDARD POTASSIUM DICHROMATE AND

ESTIMATION OF FERROUS IRON

Aim:

To prepare standard potassium dichromate solution and to estimate the amount of

ferrous ion present in the given sample.

Apparatus:

Burette, Pipette, Conical flask, Funnel, Standard flask, Weighing bottle, Weighing box,

and Fractional weighing box.

Principle:

Ferrous iron is estimated by titrating against standard potassium dichromate solution

using diphenyl amine as an indicator.

K2Cr2O7 + 6FeSO4 + 7H2SO4 K2SO4 + Cr2(SO4)3 + 3Fe(SO4)3 + 7H2O

1mole of K2Cr2O7 = 6 moles of FeSO4

Procedure:

Titration I: Standardization of K2Cr2O7 solution.

The burette is washed with distilled water and rinsed with K2Cr2O7 then filled with

K2Cr2O7 without any air bubbles along with the nozzle from zero. Initial reading of the

burette is noted. 20Ml of standard Mohr’s salt solution is pipetted out into a clean conical

flask, then 5Ml of H2SO4& H3PO4 mixture is added in it. 2-3 drops of diphenylamine

indicator is added to the conical flask. Then it is titrated with dichromate solution. The

solution colour turns to green; titration is continued until green colour is turned into bluish

violet colour. The end point is noted. The titration is repeated until the two concordant values

are obtained.


(AUTONOMOUS)

35

Titration II:

Estimation of ferrous ion in Mohr’s salt solution

S.NO Volume of FAS

(Ml)

Burette Reading



1

2

3

4

5

Calculation

Volume of K2Cr2O7 (V1) = Ml

Normality of K2Cr2O7 (N1) = N

Volume of FAS (V2) = 20 Ml

Normality of FAS (N2) = ?

V1N1= V2N2

2

112

V

VNN

=

= __________ N

Weight of ferrous ion present in given 100 Ml of FAS solution = 10

8.552 Ng

=

= ___________ g


(AUTONOMOUS)

36

Titration II: Estimation of ferrous ion in Mohr’s salt Solution:

The test solution is given in 100Ml standard flask. 20Ml of solution is pipetted out into

a clean conical flask and 5Ml of H2SO4& H3PO4 acid mixture is added to this solution. 2 –

3drops of diphenylamine indicator is added into conical flask, immediately the solution turns

into green colour and is titrated against K2Cr2O7 till green colour change into bluish violet

colour at the end point. The burette reading is noted. The titration is repeated to get

concordant values.

Result:

The amount of ferrous ion 100Ml of given solution = ______________ g



CO1 √

CO2 √

CO3 √

CO4 √

CO5 √

CO6 √

CO7 √


(AUTONOMOUS)

37

Titration I

Standardization of sodium thiosulphate (hypo) solution

S.NO Volume of

CuSO4 (Ml)

Burette reading



Calculation

Volume of CuSO4 (V1) = 20 Ml

Normality of CuSO4 (N1) = 0.01 N

Volume of hypo (V2) = Ml

Normality of hypo (N2) = ?

V1N1= V2N2

2

112

V

VNN

=

= __________ N


(AUTONOMOUS)

38


PREPARATION OF STANDARD POTASSIUM DICHROMATE AND

ESTIMATION OF COPPER BY IODOMETRY

Aim:

To estimate the amount of copper present in a given solution by iodometry method.

Apparatus:

Burette, Pipette, Standard flask, Conical flask.

Principle:

Iodometric determination of copper is based on the following reaction

Cu2+

ions gain an electron from I– ions and reduced to Cu

+ ions which is then

precipitated as cuprous iodide. Excess of KI is added to prevent the absorption of iodine on

cuprous iodide. Ammonium thiocyanate is added towards the end of the titration which

converts cuprous iodide into less soluble cuprous thiocyanate.

Procedure:

Titration I

Standardization of sodium thiosulphate (hypo) solution

The burette is washed with distilled water and rinsed with hypo solution and then filled

with the same solution. Take 20Ml of known CuSO4 solution in a clean conical flask and add

Na2CO3 solution drop wise till a blue turbidity appears. Dissolve the turbidity by adding

dilute acetic acid drop wise. Then add 10Ml of 10% KI solution.

The titration is started with hypo solution till the conical flask solution becomes light

yellow. Then add two drops of starch solution and a pinch of solid ammonium thiocyanate.

Titration is continued till the blue colour of starch solution disappears. The volume of hypo is

noted. The titration is repeated till concordant values are obtained.

2Cu2+ + 4I- 2CuI + I2

2S2O32- + I2 S4O6

2- + 2 I-


(AUTONOMOUS)

39

Titration II: Estimation of amount copper in unknown solution

S.NO Volume of

CuSO4 (Ml)

Burette reading



Calculation

Volume of hypo (V1) = Ml

Normality of hypo (N1) = N

Volume of CuSO4 (V2) = 20 Ml

Normality of CuSO4 (N2) = ?

V1N1= V2N2

2

112

V

VNN

=

= __________ N

Weight of copper present in given 100 Ml CuSO4 solution = g

=

Weight of copper present in given 100 Ml CuSO4 solution = ______________ g


(AUTONOMOUS)

40

Titration II

Estimation of copper in unknown solution

The burette is filled with hypo solution. The unknown CuSO4 solution is given in

standard flask. The solution is made up to 100Ml using distilled water. 20Ml of this unknown

CuSO4 solution is taken in a clean conical flask and add Na2CO3 solution drop wise till a blue

turbidity appears. Dissolve the turbidity by adding dilute acetic acid drop wise. Then add

10Ml of 10% KI solution.

The titration is started with hypo solution till the conical flask solution becomes light

yellow. Then add two drops of starch solution and a pinch of solid ammonium thiocyanate.

Titration is continued till the blue colour of starch solution disappears. The volume of hypo is

noted. The titration is repeated till concordant values are obtained.

Result:

The amount of copper present in given 20 Ml CuSO4solution = ___________ g.



CO1 √

CO2 √

CO3 √

CO4 √

CO5 √

CO6 √

CO7 √


(AUTONOMOUS)

41

S.NO Volume of

NaOH (Ml)

Observed Conductance

C in mhos

Corrected Conductance


(AUTONOMOUS)

42


DETERMINATION OF STRENGTH OF THE GIVEN

HYDROCHLORIC ACID AGAINST STANDARD SODIUM

HYDROXIDE SOLUTION BY CONDUCTOMETRIC TITRATION Aim:

To determine the strength of strong acid using strong base by Conductometry.

Apparatus:

Conductivity Bridge, Conductivity cell, Micro burette, 100Ml beakers, Standard flask.

Chemical Equation:

(H+ + Cl-) + (Na+ + OH-) Na+ + Cl- + H2O

Principle:

The conductivity of the solution is mainly due to H+ ions of strong acid HCI. The

solution initially contains H+ and Cl

– ions and the H

+ ions move with greater mobility. When

NaOH is added in to the solution, the conductance slowly decreases, because H+ ions react

with OH– ions and form water. At neutralization point minimum conductance is observed.

After the neutralization, the conductance gets increases due to conductance of OH– ions

obtained from NaOH.

So initially we observe high conductance values and gradually conductance decreases

and then increases.

Procedure:

Standard solution of NaOH is prepared by taking 4g of NaOH in 100 Ml standard

flask. Unknown HCl Solution is taken in a clean 100 Ml beaker. 20 Ml of water and 20 Ml of

unknown HCl solution are taken in a conductivity cell and kept in a thermostat. The

conductivity of the solution is measured.NaOH solution is taken in to a micro burette and

fitted to a stand above conductivity cell. 0.5Ml of NaOH is added to the acid solution and

stirred well and conductance is measured, similarly the values are noted for 0.5,1.0,1.5

.......Ml etc. of NaOH and conductance values are measured up to the increasing the

conductance values. After the raising in conductance values, at least five readings are noted

by adding NaOH to the conductivity cell.


(AUTONOMOUS)

43

Calculations

Volume of NaOH V1= ________ Ml (from graph)

Normality of NaOH N1= 0.01 N

Volume of HCl V2= 10 Ml

Normality of acid N2 = ?

V1N1= V2N2

2

112

V

VNN

=

Normality of acid =


(AUTONOMOUS)

44

Graph:

A graph is plotted between corrected conductance C and volume of NaOH added. The

graph is obtained as follows.

The corrected conductance is measured by using the formula.

C = Measured conductance

C '= Corrected conductance

V = Volume of acid + Volume of Water

U = Volume of base.

Precautions:

1. The cell should never kept dry.

2. The electrode must be warmed.


(AUTONOMOUS)

45

Result:

The strength of HC1 is determined conductometrically and is found to be = __________ N



CO1 √

CO2 √

CO3 √

CO4 √

CO5 √

CO6 √

CO7 √


(AUTONOMOUS)

46

Conductometric titration: BaCl2vs Na2SO4

S.No.

Volume of

Na2SO4

(ML)

Observed

Conductance

C in mhos

Corrected Conductance


(AUTONOMOUS)

47


CONDUCTOMETRIC TITRATION OF BaCl2vs Na2SO4

(PRECIPITATION TITRATION)

Aim:

To estimate the strength and amount of BaCl2in the given solution by conductometric

titration using standard Na2SO4solution.

Apparatus:

Conductivity Bridge, Conductivity cell, Micro burette, 100mL beakers and Standard

flask.

Chemicals required:

Standard Na2SO4solution and BaCl2,

Principle:

Conductometric titration is based on the measurement of the electrical conductivity of

the solution. The electrical conductivity of the solution is purely due to the movement of ions.

During the reaction between BaCl2 and Na2SO4, barium sulphate is precipitated out. During

this precipitation process, conductivity decreases slowly up to the end point. After the end

point there is a sharp increase in conductivity. It is due to presence of Na+& SO4

2– ions.

BaCl2 + Na2SO4 → BaSO4↓ + 2NaCl

Procedure:

Initially burette is washed with distilled water & rinsed with standard sodium sulphate

solution. Then the burette is filled with standard Na2SO4 solution without any air bubbles.

The BaCl2 solution is given in standard flask. The volume is made up to 100mL using

distilled water. 20mL of BaCl2 solution is pipetted out into a clean beaker and 20mL

deionized water is added into a beaker. Conductivity cell is immersed in a beaker and initial

conductivity value is noted. Na2SO4 solution from burette is added to a beaker by 1mL

interval and solution is stirred using glass rod. The conductivity values are noted for every

addition of Na2SO4. Initially the conductance value decreases gradually up to the equivalent

point and then increases sharply. The titration is continued for further 5 to 7 values after

getting the end point.


(AUTONOMOUS)

48

Calculations

Volume of Na2SO4 V1= ________ mL (from graph)

Normality of Na2SO4 N1= 0.02 N

Volume of BaCl2 V2= 20 mL

Normality of BaCl2 N2 = ?

N1V1 = N2V2

N2=

=

N2 = …………….N

Strength of BaCl2 N2= …………….N

The amount of BaCl2 present in 1 L of the given solution = N2 x 104.12 (Eq. wt. of BaCl2)

=

= ……………. g/L

The amount of BaCl2 present in 100 mL of the given solution = g

=

= ……………. G


(AUTONOMOUS)

49

Graph

The corrected conductance is measured by using the formula.

C = Measured conductance

C '= Corrected conductance

V =Volume of Water + Volume of BaCl2

U = Volume of Na2SO4

Result:

The strength of BaCl2 determined by conductometric titration = …………….N

The amount of BaCl2 present in 100 mL of the given solution = …………….g



CO1 √

CO2 √

CO3 √

CO4 √

CO5 √

CO6 √

CO7 √


(AUTONOMOUS)

50


DETERMINATION OF VISCOSITY OF OILS USING REDWOOD

VISCOMETER AIM:

Determination of viscosity of lubricating oil by Redwood viscometer-I.

APPARATUS REQUIRED:

Redwood viscometer-I,

Thermometers,

Stopwatch and

Kohlrausch flask.

MATERIALS REQUIRED:

Given sample of lubricating oil.

DESCRIPTION OF THE

APPARATUS: Oil cup:

It is 90mm in height and 46.5mm in diameter silver plated brass cylinder.

Its upper end is open.

Its lower end is fitted with an agate jet having bore of diameter 1.62mm and length 10mm.

The jet can be opened and closed by a valve rod.

The valve rod is a small silver plated brass ball fixed to a stout wire.

There is a pointer to indicate the level to which the cylinder is to be filled with oil.

The pointer is fixed on the inner side of the cylinder.

The cover of the cup is fitted with a thermometer to indicate the temperature of the oil.

Heating bath:

There is a cylindrical copper bath which surrounds the oil cup.

This copper bath contains water.

It is provided with an out let tap to let out water from it and a long side tube projection

outwards.

This is needed to heat the bath water by means of a burner.

There is a thermometer to indicate the temperature of water.

Stirrer:

The heating bath is provided with a stirrer which stirs the water in the heating bath for

maintaining uniform desired temperature. The stirrer is sealed at the top to prevent water

rushing into the oil cylinder.

Spirit level:

The cover of the cup is provided with a spirit level for vertical leveling of the jet.

Leveling screws:

The entire apparatus rests on three legs provided at the bottom with leveling screws.

Kohlarausch flask:

This flask receives the oil from jet outlet. Its capacity is 50Ml up to the mark in its neck


(AUTONOMOUS)

51

PROCEDURE:

Clean the oil cup with the help of a suitable solvent and properly remove any trace of the solvent.

Fill the bath with water to determine viscosity at 800C and below. For higher temperature

fill the bath with oil having suitable viscosity at the test temperature. Keep the brass ball in

position so as to seal the orifice. Now pour the supplied oil sample under test carefully into

the oil cup up to the mark. Keep the Kohlarausch flask in the position below the jet Insert a

thermometer and a stirrer and cover the lid. Keep stirring the water in the bath and oil in the

oil cup and adjust the bath temperature until the oil attains the desired constant

temperature. When the temperature of the oil has become quite study in the oil cup and shows a

constant reading, lift the ball valves and simultaneously start the stopwatch. Allow the oil to

fill in the flask up to 50Ml mark. Stop the stopwatch and note down the time in seconds.

Replace the ball valve in the position to seal the cup to prevent overflow of the oil. Again

refill the oil cup up to the mark and repeat the experiment to get nearly reproducible results. Repeat

the experiment at five elevated temperatures say 400C, 500C, 600C, 700C and 800C and

note the respective time of flow as described below.

DISCUSSION:

Viscosity is one of the most important properties of any lubricating oil. This indicates us

about the suitability of the oil for lubricating purpose. A lubricant must reduce friction

between sliding parts of any machine. This avoids the direct metal to metal contact. The

main criteria of a lubricant are that it should be sufficiently viscous under high temperature

and pressure exerted by the machine to adhere to the surface. If the viscosity is low then a thin

film of lubricant cannot adhere to the sliding surfaces. In case the viscosity is high there will

be excessive friction. The absolute viscosity of fluid oil can be determined by measuring the

rate of flow of the oil through a capillary tube kept at a uniform temperature.

But in case of lubricating oil specific viscosity is generally determined by measuring

the time taken for a given quantity of oil to flow through an orifice or jet of standard

dimension under standard conditions. Measurement of viscosity of lubricating oil is made

with the help of an apparatus called Redwood viscometer. Redwood viscometer is commonly

used for determining viscosities of thin lubricating oils. There are two types of Redwood

viscometers i.e., Redwood viscometer No.1 and Redwood viscometer No.2. Redwood

viscometer No.1 will correctly indicate the viscosity of a liquid having time flow between 30

seconds to 2000 seconds If the time flow measured with this apparatus for any oil exceeds

2000 seconds, the test should be repeated with Redwood viscometer No.2 which will give

the correct value of viscosity for such highly viscous oil.


(AUTONOMOUS)

52

TABLE:

S.NO.

Temperature(0C)

Time to fill 40

CC of Oil

Trial-I Trial-II Trial-III Average

Time

1

2

3

4

5

CALCULATIONS FORMULAE:

The ratio of absolute viscosity to density for any fluid is known as its

absolute kinematic viscosity.

Since the instruments used are of standard dimensions, kinematic viscosity of the oil

in Centi stokes can be calculated from the time taken by the oil to flow through the

standard orifice of the instrument with the help of following equation.

The viscosity of the given oil sample with the help of Redwood viscometer at t0C =

…................ Redwood seconds V= At-B/T

Where, V = Kinematic viscosity of the oil in

t = Time of flow in seconds

A & B are instrument constants.

A = 0.264 and B = 190,

T= Temperature


(AUTONOMOUS)

53

CALCULATIONS: 1. At 40

0 c the viscosity of the 2T- oil = At-B/T

= 2. At 50


= 3. At 60


= 4. At 70


= 5. At 80



(AUTONOMOUS)

54

Result:

1. At 400 c the viscosity of the 2T- oil =

2. At 50

0 c the viscosity of the 2T- oil =

3. At 60


4. At 70


5. At 80




CO1 √

CO2 √

CO3 √

CO4 √

CO5 √

CO6 √

CO7 √


(AUTONOMOUS)

55

TABLE 1: RUBRICS FOR CHEMISTRY LAB

Excellent(3) Good(2) Fair(1)

nduct

Experiments

(CO1)

Student successfully

completes

the experiment, records

the data,

analyzes the experiment's

main

topics, and explains the

experiment concisely and

well.

Student successfully completes

the experiment, records the

data, and analyzes the

experiment's main topics

Student

successfully

completes

the experiment,

records the

data, and unable to

analyzes.

Analysis and

Synthesis

(CO2)

Thorough analysis of

Copper

Reasonable analysis of Copper Improper analysis

of Copper

Complex

Analysis &

Conclusion

(CO3)

Thorough comprehension

through analysis

Reasonable comprehension

through analysis

Improper

comprehension

through analysis

Lab safety

(CO4)

Student will demonstrate

good

understanding and follow

lab safety

Student will demonstrate good

understanding of lab safety

Students

demonstrate a little

knowledge of lab

safety.

Ability to

work in

teams

(CO5)

Performance on teams is

excellent with clear

evidence of equal

distribution of tasks and

effort

Performance on teams is good

with equal distribution of tasks

and effort

Performance on

teams is acceptable

with one or more

members carrying

a larger amount of

the effort

Report

Writing

(CO6)

Status report with clear

and logical sequence of

parameter using excellent

language

Status report with logical

sequence of parameter using

understandable language

Status report not

properly organized

Continuous

learning

(CO7)

Highly enthusiastic

towards continuous

learning

Interested in continuous

learning

Inadequate interest

in continuous

learning

ENGINEERING CHEMISTRY LAB MANUAL - sitams.org

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