18002_CHE010 final

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LMCHE010

LABORATORY MANUAL

CHE010

BASIC CHEMISTRY LABORATORY

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LMCHE010

TABLE OF CONTENTS

S. No. Title of the Experiment Page No.

1 To detect the presence of acid radicals (oxyanions - carbonate, sulphate

and nitrate) in a given salt.

4-8

2 To detect the presence of acid radicals (halides - chloride, bromide and

iodide) in a given salt.

9-13

3 To detect the presence of basic radicals (Gp I, II Pb

+2, Cu

+2).

14-18

4 To detect the presence of basic radicals (Gp III Al

+3, Fe

+2,Cr

+3).

19-23

5 To detect the presence of basic radicals (Gp IV, V Zn

+2,Ni

+2,Ca

+2,Ba

+2).

24-30

6 To detect the presence of basic radicals (Gp VI Mg+2

, K+, NH4

+). 31-35

7 To detect the presence of one cation and one anion from a given mixture.

36-41

8 To determine Electrochemical Chemical Equivalent of Copper using

Copper sulphate solution and Copper electrodes.

42-46

9 To determine the percentage of iron in the given ferrous alloy by

potassium permanganate method.

47-50

10 To prepare phenol formaldehyde resin (bakelite). 51-53

11 To determine carbon monoxide content in emission from petrol vehicle.

54-56

12 To determine dissolved oxygen in a water sample. 57-61

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Some rules to be followed in the Lab:

GENERAL RULES:

1. Entry without lab coat in chemistry lab is strictly prohibited.

2. Mobile phones should be switched off and kept in the bag during lab hours.

3. No group discussions are allowed in the lab.

4. Clean the apparatus as well as the slab after your experiment is finished.

5. Do not do any undisciplined activity in lab as you are under strict cc-TV surveillance.

6. Do not use laptop while performing the experiments.

7. Switch off electrical apparatus after their use.

8. Do not throw filter papers in sink, dispose all waste in dustbin.

PRECAUTIONARY RULES:

1. Never pipette out strong acids and base with your mouth, it can be dangerous, therefore use

measuring cylinders for such chemicals.

2. Never try to smell the chemicals as it can be dangerous for you.

3. Cap the bottles after taking chemical as uncovered bottles can be a source of harmful fumes.

4. In case of any accidental spill over of any chemical on you, report your teacher or lab

technician immediately.

5. Report your lab technician if any breakage of glass apparatus takes place.

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LMCHE010

EXPERIMENT NO. 1

Aim: To detect the presence of acid radicals (oxyanions: carbonate, nitrate and sulphate) in a

given salt.

Equipments to be used: Test tube, test tube holder, Bunsen burner, tripod stand, test tube and watch

glass.

Chemicals required: Inorganic salt, conc. H2SO4, Dil. H2SO4,

Learning objective: (i) Student will be able to understand that anions detected by dil. and conc.

H2SO4 tests can be detected by the evolution of different gases.

(ii) Some of the anions like SO42-

which are not evolved as gases on treatment with by dil. and

conc. H2SO4 tests, can be detected by their independent tests.

Outline of the procedure:

Preparation of Salt solution:

1. Preparation of Water extract (for water soluble salts): Dissolve a small amount of salt in 2-3 mL of

distilled water, filter it and collect the filtrate for various tests.

2. Preparation of Sodium Carbonate extract (for water insoluble salts): Boil a small amount of salt

with 300-400 mg solid sodium carbonate and add 5-6 mL of distilled water, filter and collect the

filtrate for various identification tests.

Test for detection of carbonate

S.No. Experiment Observation Inferance

1 Dilute H2SO4 test: To the small

amount of salt add 1-2 mL of dil.

H2SO4

Colourless, odourless

gas evolved with brisk

effervesnce

CO32-

present

Confirmatory test for Carbonate:


1 Lime water test: Pass the gas through

lime water

Lime water turns

milky

CO32-

confirmed

2 Pass more of the gas through lime

water

Milkiness disappears CO32-

confirmed

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Test for detection of nitrate (NO3-)


1 Dilute H2SO4 test: To the small amount

of salt add 1-2 mL of dil. H2SO4

No gas evolved CO32-

absent

2 Conc. H2SO4 test: Heat a small amount

of salt with conc. H2SO4

Colourless gas evolved NO3- present

Confirmatory test for Nitrate:


1 Add copper turnings to the above test

tube

Brown fumes intensify NO3- confirmed

2 Ring test: To water extract, add

freshly prepared ferrous sulphate

and mix thoroughly. Cool the

mixture under the tap. Add 2 mL

conc. H2SO4along the sides of

the test tube without shaking.

A dark brown ring

is formed at the

junction of the two

solutions.

NO3- confirmed

Test for detection of sulphate (SO42-

)





absent

2 Concentrated H2SO4 test : Heat a

small amount of salt with conc. H2SO4

No gas evolved NO3- absent

3 BaCl2 test: Take 1 mL water extract of

the salt in water or sodium carbonate

and after acidifying with dilute

hydrochloric acid add BaCl2 solution.

White precipitate

insoluble in conc. HCl

or conc. HNO3 is

obtained.

SO42-

present

4 Lead acetate test: To the water extract

or sodium carbonate extract add glacial

acetic acid and lead acetate solution.

Appearance of white

precipitate

SO42-

confirmed

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Required Results: The given salt contains ________________________anion.

Parameters: NA

Relationship: NA

Graphs: NA

Error Analysis: NA

Cautions:

i. Since the experiment deals with acidic and basic conditions. The acids and the bases

should be handled with care and dropper or a measuring cylinder should be used for

addition of it.

ii. Bases like NH4OH and conc. HNO3, HCl, H2SO4 should be used carefully, since they fume

in air the bottle should be corked immediately after its use.

iii. Many solution bumps out while heating; test tube should be kept in a slant position with

its mouth away from the person carrying the experiment to avoid bumping on face.

iv. Concentrated acids should be added along the sides of the testube.

Requirements for Lab Technician:

1. Inorganic salt samples (Salts containing nitrate, sulphate and carbonate)

2. Dil. H2SO4

3. Conc. H2SO4

4. BaCl2 solution

5. Lime water

6. Glacial acetic acid

7. Lead acetate solution

8. Copper turnings

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Date of Performance: ________ Worksheet of the student Registration No.______________

Aim: To detect the presence of acid radicals (oxyanions: carbonate, nitrate and sulphate) in a

given salt.

Observation table:

Sample Experiment Observation Inferance

A

B

C

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Results and Discussion:

Learning Outcomes (what I have learnt): to be written by the students in 50-70 words.

To be filled in by faculty

S.No Parameter (Scale from 1-10, 1 for

very poor and 10 excellent)

Marks Obtained Maximum

Marks

1 Understanding of the student about the

procedure/apparatus.

20

2 Observations and analysis including

learning outcomes

20

3 Completion* of experiment, Discipline

and Cleanliness

10

Signature of Faculty Total marks Obtained

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EXPERIMENT NO. 2

Aim: To detect the presence of acid radicals (halides: chloride, bromide and iodide) in a given

salt.

Equipments to be used: Test tube, test tube holder, Bunsen burner, tripod stand, test tube stand and

watch glass.

Chemicals required: Sample salt, Dil. H2SO4, Conc. H2SO4.

Learning objective: (i) To detect various halogens present in the given salt

(ii) To identify and differentiate them on the basis of Silver nitrate test


Preparation of Salt solution:

1. Preparation of Water extract (for water soluble salts): Dissolve a small amount of salt in 2-3 mL of

distilled water, filter it and collect the filtrate for various tests.

2. Preparation of Sodium Carbonate extract (for water insoluble salts) : Boil a small amount of salt with

300-400 mg solid sodium carbonate and add 5-6 mL of distilled water, filter and collect the filtrate for

various identification tests.

Test for detection of halides





absent

2 Concentrated H2SO4 test: Heat a small

amount of salt with conc. H2SO4

A colourless gas with

pungent smell,which

gives dense white fumes

when a rod dipped in

ammonium hydroxide is

brought near the mouth

of the test tube.

Cl- present

Reddish brown colour

gas with pungent odour

is evolved

Br- present

Violet vapours I- present

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Confirmatory test for halides:


Confirmatory test for chloride

1 MnO2 test: Add a pinch of MnO2 to

above colourless gas

greenish yellow gas

evolves

Cl- confirmed

2 AgNO3(Silver nitrate) test: To

Soda extract/ water extract, add

HNO3 till effervescence stops,

heat and then add AgNO3 solution

curdy white ppt is

obtained which is

soluble in NH4OH

and which disappear on

addition of dil. HNO3.

Cl- confirmed

Confirmatory test for bromide

3 AgNO3(Silver nitrate) test: To

Soda extract/ water extract, add

dil. HNO3 till effervescence stops,

heat and then add AgNO3 solution

yellow ppt is obtained

which is soluble in

NH4OH and which

disappear on addition of

dil. HNO3.

Br- confirmed

4 To Soda extract/ water extract,

add dil HNO3, then 3-4 mL

carbon tetrachloride/ carbon

disulphide and 1 mL of conc.

HNO3. Shake vigorously.

Organic layer turns

orange

Br- confirmed

Confirmatory test for iodide:

5 Take 1 mL of salt solution neutralised

with HCl and add 1 mL chloroform/

carbon tetrachloride/carbon

disulphide. Now add an excess of

chlorine water drop wise and shake

the test tube.

A violet colour appears

in the organic layer

I- confirmed

6 AgNO3 (Silver nitrate) test: Take

1 mL of sodium carbonate

extract acidify it with dil. HNO3

(or take water extract). Add,

silver nitrate solution.

A yellow precipitate

insoluble in NH4OH

solution is obtained.

I- confirmed

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Required Results: The given salt contains ______________anion

Parameters: NA

Relationship: NA

Graphs: NA

Error Analysis: NA

Cautions:

1. Since the experiment deals with acidic and basic conditions. The acids and the bases should be

handled with care and dropper or a measuring cylinder should be used for addition of it.

2. Bases like NH4OH and conc. HNO3, HCl, H2SO4 should be used carefully, since they fume in air

the bottle should be corked immediately after its use.

3. Many solution bumps out while heating; test tube should be kept in a slant position with its

mouth away from the person carrying the experiment to avoid bumping on face.


1. Inorganic salt samples (Salts containing chloride, bromide and iodide)

2. Dil. H2SO4

3. Conc. H2SO4

4. AgNO3 solution

5. Manganese dioxide

6. Dil. HNO3

7. Conc. HNO3

8. Carbon disulphide

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Aim: To detect the presence of acid radicals (halides: chloride, bromide and iodide) in a given

salt.

Observation table:

Sample Experiment Observation Inference

A

B

C

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Marks



20


learning outcomes

20


and Cleanliness

10


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LMCHE010

EXPERIMENT NO.3

Aim : To detect the presence of basic radicals (Gp I,II Pb+2

,Cu+2

)

Equipments to be used: Test tube, test tube holder, Bunsen burner, tripod stand, test tube

and watch glass.

Chemicals used: Inorganic sample, Dil. HCl, Conc. HCl, H2S.

Learning Objectives: (i) The purpose of the experiment is to make the students

understand how the basic radicals are classified into six groups.

(ii) Student shall come to know that the cations of group I are precipitated as chlorides by

adding dil. HCl.

(iii) Student will also understand that the cations of group II are precipitated only in group

II as their sulphides in the acidic medium on passing H2S.


Preparation of Original Solution (O.S.): Dissolve 0.1 g of salt in water, dil. HCl

or conc. HCl as per solubility

Analysis of Group I


1 To aqueous solution of salt, add 5-10

drops of dil. HCl

White ppt Gp I (Pb2+

present)

Wash the residue with water and heat. Centrifuge and collect the filterate and residue.

2. To the filtrate, add 3-5 mL of dil. H2SO4 White ppt Pb

2+ is confirmed.

3. To the filtrate, add 3-5 mL of KI and

ammonium acetate

Yellow ppt Pb

2+ is confirmed.

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Analysis of Group II


1 To Original solution (O.S) add 5-10

drops of dil. HCl

No ppt. Gp I absent

2. Pass H2S to small portion of acidic

solution (dil. HCl). Filter and collect

the residue.

Black ppt. Gp II present

(I) Boil the precipitate of Group II A with dilute nitric acid and add a few drops of alcohol and

dil. H2SO4. Filter the residue

a) White ppt. Pb2+

may be present

Dissolve the precipitate in ammonium

acetate solution. Acidify with glacial

acetic acid and divide the solution into

two parts.

(i) To the first part add potassium

chromate (K2CrO4) solution.

(ii) To the second part, add

potassium iodide solution.

Yellow ppt. of lead

chromate (PbCrO4)

Yellow ppt. of lead

iodide (PbI2)

Pb2+

confirmed

Pb2+

confirmed

(b) If no precipitate is

formed, Pb

2+ absent, Cu

2+

may be present

(i) Add excess of ammonium

hydroxide solution.

(ii) Acidify it with glacial acetic

acid and add potassium

ferrocyanide solution.

Blue solution is formed

Chocolate brown ppt

Cu2+

is confirmed

Cu2+

is confirmed

Required Results: The given salt contains _______________ cation.

Parameters: NA

Relationship: NA

Graphs: NA

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Error Analysis: NA

Cautions:

1. Since the experiment deals with acidic and basic conditions. The acids and the bases


addition of it.

2. Bases like NH4OH and conc. HNO3, HCl, H2SO4 should be used carefully, since they fume


3. Many solution bumps out while heating; test tube should be kept in a slant position with



1. Inorganic salt samples (Salts containing Cu2+

and Pb2+

)

2. Dil. HCl

3. Dil. H2SO4

4. H2S gas

5. Potassium iodide

6. Ammonium acetate

7. Potassium chromate


9. Ammonium hydroxide

10. Potassium ferrocyanide

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Aim: To detect the presence of basic radicals (Gp I, II Pb+2

, Cu+2

)

Observation table:


A

B

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Marks



20


learning outcomes

20


and Cleanliness

10


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LMCHE010

EXPERIMENT NO. 4

Aim: To detect the presence of basic radicals (Gp III Al+3

,Fe+2

,Cr+3

)


and watch glass.

Chemicals used: Inorganic salt, dil. HCl, Conc. HCl, H2S, NH4Cl, NH4OH.

Learning Objectives: (i) Student will be able to understand how Al+3

, Fe+2

, Fe3+

and Cr+3

are precipitated as hydroxides in alkaline medium.

(ii) Student will be able to distinguish between Fe2+

and Fe3+

.


Preparation of O.S.: Dissolve 0.1 g of salt in water, dil. HCl or conc. HCl as per

solubility

Analysis of Cations:



drops of dil. HCl No ppt.

Gp I absent

2. Pass H2S to small portion of acidic


the residue.

No ppt Gp II absent

3. Add 2-3 drops of conc. HNO3 to O.S.,

which oxidise Fe2+

ions to Fe3+

ions.

Heat the solution for a few minutes.

After cooling add a small amount of

solid ammonium chloride (NH4Cl) and

an excess of ammonium hydroxide

(NH4OH) solution till it smells of

ammonia. Shake the test tube.

Brown or white ppt Gp III present

Collect the residue and add 3-4 mL of water and then add 100 mg sodium peroxide. Separate the residue

and filtrate.

(a) To the above residue add dil. HCl and

divide the solution in 3 parts.

Brown ppt Iron Fe2+

/ Fe3+

present

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(i) To part 1, add potassium

ferricyanide K3[Fe(CN)6] solution

(ii) To part 2 add potassium

ferrocyanide K4[Fe(CN)6]

solution

(iii) To part 3 add ammonium

thiocyanate (NH4CNS)

Blue ppt

Dark blue ppt

Blood red ppt

Fe2+

confirmed

Fe3+

confirmed

Fe3+

confirmed

(b) Divide the filtrate in 2 parts. If filtrate is yellow Cr3+

is present

(i) To part 1, add 3-4 mL of

glacial acetic acid and then 3

mL of lead acetate solution

Yellow ppt Cr3+

confirmed

(ii) To part 2 of filtrate, add

NH4Cl and heat White ppt Al3+

present

Dissolve the white precipitate in dilute HCl and divide into two parts.

(i) To the first part add sodium

hydroxide solution and warm. White ppt soluble in

sodium hydroxide Al3+

confirmed

(ii) To the second part first add blue

litmus solution and then ammonium

hydroxide solution drop by drop along

the sides of the test tube.

Blue floating mass in

colourless liquid is

obtained Al

3+ confirmed

Required Results: The given salt contains ___________cation.

Parameters: NA

Relationship: NA

Graphs: NA

Error Analysis: NA

Cautions:

i. Since the experiment deals with acidic and basic conditions. The acids and the

bases should be handled with care and dropper or a measuring cylinder should be

21

LMCHE010

used for addition of it.

ii. Bases like NH4OH and conc. HNO3, HCl, H2SO4 should be used carefully, since they

fume in air the bottle should be corked immediately after its use.

iii. Many solution bumps out while heating; test tube should be kept in a slant position

with its mouth away from the person carrying the experiment to avoid bumping on

face.


1. Inorganic salt samples (Salts containing Al3+

, Fe2+

, Fe3+

and Cr3+

)

2. Dil. HCl

3. Dil. H2SO4

4. H2S gas

5. Ammonium chloride


7. Sodium peroxide

8. Potassium ferricyanide

9. Ammonium thiocyanate



12. Lead acetate

13. Sodium hydroxide

14. Blue litmus

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Aim: To detect the presence of basic radicals (Gp III Fe+2

, Fe+3

, Cr+3

, Al3+

)

Observation table:


A

B

C

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D







Marks



20


learning outcomes

20


and Cleanliness

10


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EXPERIMENT NO. 5

Aim: To detect the presence of basic radicals (Gp IV, V Zn+2

, Ni+2

, Ca+2

, Ba+2

)


and watch glass.

Chemicals used: Inorganic salt, dil. HCl, Conc. HCl, H2S, NH4Cl, NH4OH and

(NH4)2CO3.

Learning Objectives: (i) Student will be able to know that group IV cations i.e. Zn+2

and

Ni+2

are precipitated as sulphides in alkaline medium on passing H2S.

(ii) Student will be able to distinguish between Zn2+

and Ni2+

by various tests.

(iii) Student will be able to know that the cations of group V are precipitated as their

carbonates in alkaline medium by the action of ammonium carbonate.



solubility

Analysis for Gp IV cations:

S.No. Experiment Observation Inference


drops of dil. HCl No ppt. Gp I absent

2.

Pass H2S to small portion of acidic


the residue.

No ppt Gp II absent

3.

Add 2-3 drops of conc. HNO3 to O.S.,







No ppt Gp III absent

4 Pass H2S to above alkaline solution,

shake and filter Black or white ppt Gp IV present

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If White ppt, then Zn2+

may be present. Dissolve the precipitate in dilute HCl by boiling. Divide the

solution into two parts.

(a)

(i) To one part, add sodium hydroxide

solution.

White precipitate

soluble in excess of

sodium hydroxide

solution

Zn2+

confirmed

(ii) Neutralise the second part with

ammonium hydroxide solution and add

potassium ferrocyanide K4[Fe(CN)6]

solution

Bluish ppt Zn2+

confirmed

(b) If black ppt, then Ni2+

may be present

(i) DMG test: Dissolve the precipitate

in aqua regia (3 drops of conc. HNO3

and 6 drops of conc. HCl). Heat

thesolution to dryness and cool.

Dissolve the residue in water. Add

ammonium hydroxide solution till it

becomes alkaline. Add a few drops of

dimethyl glyoxime and shake the test

tube.

Dark red ppt Ni2+

confirmed

Analysis for Gp V cations:




2.



the residue.

No ppt Gp II absent

3.









4 Pass H2S to above alkaline solution,

shake and filter No ppt Gp IV absent

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5

Take original solution and add a small

amount of solid NH4Cl and an excess

of NH4OH solution followed by solid

ammonium carbonate (NH4)2CO3.

White ppt Gp V present

Preserve a part of ppt for flame test and dissolve rest of the white precipitate by boiling with dilute

glacial acetic acid and divide the solution into two parts

(i) To the first part add potassium

chromate solution.

Yellow ppt Ba

2+ confirmed

(ii) Flame test: Take a platinum wire

and dip it in conc. HCl. Heat it strongly

until the wire does not impart any

colour to the non-luminous flame.Now

dip the wire in the paste of the (Group

V) precipitate in conc. HCl. Heat it in

the flame.

Grassy green flame Ba2+

confirmed

(b) If Ba2+

is absent, then Ca2+

may be present

(i) To another part of the solution, add

ammonium oxalate solution and shake

well.

White ppt Ca2+

confirmed

(ii) Flame test: Take a platinum wire

and dip it in conc. HCl. Heat it strongly

until the wire does not impart any

colour to the non-luminous flame.Now

dip the wire in the paste of the (Group

V) precipitate in conc. HCl. Heat it in

the flame.

Brick red ppt Ca2+

confirmed

Required Results: The given salt contains ___________ cation

Parameters: NA

Relationship: NA

Graphs: NA

Error Analysis: NA

Cautions:





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face.


1. Inorganic salt samples (Salts containing Zn2+

, Ni2+

, Ca2+

and Ba2+

)

2. Dil. HCl

3. Dil. H2SO4

4. Dil. HNO3

5. H2S gas

6. Conc. HCl



9. Ammonium carbonate


11. Dimethyl glyoxime

12. Potassium chromate

13. Ammonium oxalate

14. Ethanol

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Aim: To detect the presence of basic radicals (Gp IV, V Zn+2

, Ni+2

, Ca+2

, Ba+2

)

Observation table:


A

B

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C

D

30

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Learning Outcomes (what I have learnt): to be written by the students in 50-70 words





Marks



20


learning outcomes

20


and Cleanliness

10


31

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EXPERIMENT NO. 6

Aim: To detect the presence of basic radicals (Gp VI Mg+2

, K+, NH4

+)

Equipments to be used: Test tube, test tube holder, Bunsen burner, tripod stand,test tube

and watch glass.

Chemicals used: Inorganic salt, dil. HCl, Conc. HCl, H2S, NH4Cl, NH4OH and

(NH4)2CO3.

Learning Objectives: (i) Students will be able to understand that the cations of group VI

i.e. Mg+2

, K+, NH4

+ are neither precipitated as chlorides, sulphides and carbonates.

(ii) Student will be able to detect the presence of independent cations namely Mg+2

, K+,

NH4+.

Outlines of the procedure:


solubility

Analysis for Gp VI cations:




2.



the residue.

No ppt Gp II absent

3.









4 Pass H2S through above alkaline

solution. No ppt Gp IV absent

5

Take original solution and add a small

amount of solid NH4Cl and an excess

of NH4OH solution followed by solid

ammonium carbonate (NH4)2CO3.

No ppt Gp V absent

Gp VI may be present

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Confirmatory tests for K+, Mg

2+, NH4

+

S.No Experiment

Observation Inference

1 To O.S., add dil. HCl solution. Add

NH4OH and Na2HPO4 solution. White ppt on scratching Mg

2+ confirmed

2. To O.S., add glacial acetic acid and

sodium cobalt nitrate Yellow ppt K

+ confirmed

3.

Take a platinum wire and dip it in conc.

HCl. Heat it strongly until the wire

does not impart any colour to the non-

luminous flame. Now dip the wire in

the paste of the (Group V) precipitate in

conc. HCl. Heat it in the flame.

Purple flame K+ confirmed

4. To O.S., add Nessler’s reagent

Brown ppt NH4+ confirmed

5. To O.S., add NaOH and heat

Pungent smelling gas is

evolved NH4+ confirmed

Required Results: The given salt contains _____________ cation.

Parameters: NA

Relationship: NA

Graphs: NA

Error Analysis: NA

Cautions:








face.

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1. Inorganic salt samples (Salts containing Zn2+

, Ni2+

, Ca2+

and Ba2+

)

2. Dil. HCl

3. Dil. H2SO4

4. Dil. HNO3

5. H2S gas

6. Conc. HCl




10. Sodium hypophosphate


12. Sodium cobalt nitrate

13. Nesseler’s reagent


34

LMCHE010


Aim: To detect the presence of basic radicals (Gp VI Mg+2

, K+, NH4

+)

Observation table:


A

B

C

35

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Marks



20


learning outcomes

20


and Cleanliness

10


36

LMCHE010

EXPERIMENT NO. 7

Aim: To detect the presence of one cation and one anion from a given salt


and watch glass.

Chemicals used: Inorganic salt, Dil. H2SO4, Conc. H2SO4, dil. HCl, Conc. HCl, H2S,

NH4Cl, NH4OHand (NH4)2CO3.

Learning Objectives: (i) Student will be able to detect cation and anion from any given

salt.

(ii) Student will be able to understand that the cations of group IV are not precipitated in

group II.

Outline of the procedure: As per the detection and confirmatory tests mentioned in

Experiment 1 to Experiment 6, the cation and anion can be detected from a given salt. For

example the salt under analysis is MgSO4, the procedure will be as follows:

Analysis for Anion

Preparation of Water extract (for water soluble salts): Dissolve a small amount of salt

in 2-3 mL of distilled water, filter it and collect the filtrate for various tests.



of salt add 1-2 mL of dil. H2SO4 acid


absent

2

Conc. H2SO4 test: Heat a small amount

of salt with conc. H2SO4

No gas evolved Cl-, Br

-, I

- and NO3

-

absent

3 BaCl2 test: Take 1 mL water extract of

the salt in water or sodium carbonate

and after acidifying with dilute

hydrochloric acid add BaCl2 solution.

White precipitate

insoluble in conc. HCl

or conc. HNO3 is

obtained.

SO42-

present

The anion present in the salt is SO42-

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Analysis of basic radical

Preparation of Original Solution (O.S.): Dissolve 0.1 g of salt in water or dil. HCl

or conc. HCl as per solubility.


1 To the original solution add 5-10 drops

of dil. HCl No ppt Gp I absent

2. Pass H2S gas throughabove solution. No ppt Gp II absent

3.









4 Pass H2S through above alkaline

solution. No ppt Gp IV absent

5

Take 1-2 mL original solution and add

a small amount of solid NH4Cl and an

excess of NH4OH solution followed by

solid ammonium carbonate (NH4)2CO3.

No ppt (a) Gp V absent

(b) Gp VI may be present

6 To O.S., add dil. HCl solution. Add

NH4OH and Na2HPO4 solution. White ppt on scratching Mg

2+ confirmed

The cation present in the salt is Mg2+

Required Results: The anion ____________ and cation __________________ is present in

the salt.

Parameters: NA

Relationship: NA

Graphs: NA

Error Analysis: NA

Cautions:

1. Since the experiment deals with acidic and basic conditions. The acids and the bases


addition of it.

2. Bases like NH4OH and conc. HNO3, HCl, H2SO4 should be used carefully, since they fume

38

LMCHE010


3. Many solution bumps out while heating; test tube should be kept in a slant position with



1. Inorganic salt samples (Salts containing any cation or anion)

2. Dil. HCl

3. Dil. H2SO4

4. Dil. HNO3

5. H2S gas

6. Conc. HCl




10. Sodium hypophosphate


12. Sodium cobalt nitrate

13. Nesseler’s reagent


39

LMCHE010


Aim: To detect the presence of one cation and one anion from a given mixture

Observation table: For Anion:


For Cation:


40

LMCHE010

41

LMCHE010







Marks



20


learning outcomes

20


and Cleanliness

10


42

LMCHE010

EXPERIMENT NO. 8

Aim: To determine Electrochemical Chemical Equivalent of Copper using Copper sulphate

solution and Copper electrodes

Equipments to be used: Copper voltameter, four copper plates, battery of 4 to 5 cells, a rheostat,

one way key, connecting wires, sand paper, weighing balance, ammeter and stop watch

Chemicals used: Copper sulphate, Conc.H2SO4, distilled water, dil HNO3

Learning Objectives:To know about Faraday’s first law of electrolysis: According to

Faraday’s first law of electrolysis, the electrochemical equivalent, Z, is given by the relation:

𝑍 = 𝑤

𝐼 × 𝑡

where w is the mass of metal deposited, I is the current in amperes and t is the time in seconds. If

the value of Z comes out to be fairly constant by passing the same current for different times,

first law of electrolysis is verified.

Procedure:

Clean all the copper plates with nitric acid and wash them thoroughly in running tap

water. Dry one of the plates and clean it with a piece of fine sand paper. Wash it and let it

dry. Weigh accurately.

Dissolve 30 g of powdered copper sulphate in 200 mL water by warming in beaker. Cool

the solution and add Conc. H2SO4 to it. Fill the copper voltameter with this solution.

Arrange the circuit as shown in figure

.

Take out the central plate. Measure its length and breadth dipped in electrolyte. Calculate

the area of plate and double it for total area of both sides dipped in the electrolyte. Put the

plate in electrolyte. A good deposit is obtained when a current of one ampere is passed

for every 100 sq cm of the cathode dipping in electrolyte.

43

LMCHE010

To test the connections, put the plug in key K and adjust the value of the current

approximately equal to the calculated value. See that the current remains constant for

about 5 mins. If on removing the central plate red deposits are seen on it, the connections

are correct.

Replace the central plate by the weighed copper plate, put in the key “K” and start the

stop watch. Note the reading of the ammeter at intervals and see that the current remains

constant. Adjust the current with a rheostat. Stop the stop watch after 30 minutes and at

the same time take out the plug from the key K.

Remove the cathode plate carefully, rinse it immediately in dil. H2SO4 and then wash it

thoroughly in running water. Rinse it with alcohol. Dry it and find its weight accurately.

Repeat the experiment by passing the current for 45 minutes. Note the current in ammeter

after every 15 minutes.

Calculate the electrochemical equivalent for the two observations.

Calculations: Length of the plate dipped = l cm

Breadth of the plate dipped = b cm

Total area dipped, a = 2l x b cm2

Current to be adjusted = a/100 amperes

S.No.

Initial

weight of

cathode

w1(g)

Final

weight of

cathode

w2(g)

Weight of

copper

deposited

w = w2-

w1

Current

I (A)

Time t

(s)

Electrochemical

equivalent

𝑍 = 𝑤

𝐼 × 𝑡

1.

2.

Result: The Electrochemical equivalent of copper is __________ g/C

Scope of the result: As the value of the electrochemical equivalent of copper, Z, comes out to

be fairly constant, it verifies first law of electrolysis.

Parameters: NA

Relationships to be determined: NA

Graphs/Plots: NA

Error Analysis: NA.

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LMCHE010

Cautions:

i. The cathode plate must be cleaned thoroughly, dried and weighed accurately.

ii. The current should be constant throughout the experiment and should be adjusted at the

rate of one ampere for every 100 sq.cm of the area of the copper plate dipping in copper

sulphate solution.

iii. The plates should not touch each other.

iv. The electrolyte should be fresh and free from impurities.

v. The weighed plate must be connected to the negative pole of battery.

vi. The plate must be rinsed in dilute sulphuric acid as it is removed from the electrolyte,

otherwise the deposit will turn black due to oxidation.

Requirement for Lab Technician:

1. Copper plates

2. Copper sulphate

3. Conc. H2SO4

4. Ethanol

5. Dil. HNO3

45

LMCHE010


Aim: To determine Electrochemical Chemical Equivalent of Copper using Copper sulphate

solution and Copper electrodes.

Observations and Calculations: Length of the plate dipped = l cm

Breadth of the plate dipped = b cm

Total area dipped, a = 2l x b cm2

Current to be adjusted = a/100 amperes

S.No.

Initial

weight of

cathode

w1(g)

Final

weight of

cathode

w2(g)

Weight of

copper

deposited

w = w2-

w1

Current

I (A)

Time t

(s)

Electrochemical

equivalent

𝑍 = 𝑤

𝐼 × 𝑡

1.

2.


Error Analysis:


46

LMCHE010





Marks



20


learning outcomes

20


and Cleanliness

10


47

LMCHE010

EXPERIMENT NO. 9

Aim:To determine the percentage of iron in the given ferrous alloy by potassium permanganate

method.

Equipments to be used: Titration flask, pipette, burette, beakers, glass rod, funnel and burette stand

Chemicals used:M/100 KMnO4, sample ferrous alloy solution (20g/L) and Dil. H2SO4.

Learning Objective: (i) To determine the percentage of iron in given alloy :The molarity of the given solution of alloy can be determined by titrating it with standard KMnO4 solution in which

the following redox reaction takes place which is based on the oxidation and the reduction

reaction. The oxidising agent i.e Potassium permanganate oxidises the reducing agent ferrous sulphate and ferrous ammonium sulphate in acidic medium to ferric sulphate.The strength of

alloy can be calculated and hence percentage of iron can be determined.

(ii) To understand the redox reaction in the experiment.

MnO4- + 8H

+ + 5e

- → Mn

2+ + 4H2O (Reduction)

5Fe2+

→ 5Fe3+

+ 5e- (Oxidation)

MnO4- + 8H

+ + 5Fe

2+ → Mn

2+ + 5Fe

3+ + 4H2O (Overall Reaction)

Indicator: KMnO4 acts as self-indicator.

End point: Colorless to faint pink.

Outline of Procedure

Wash the whole apparatus thoroughly with distilled water.

Rinse and fill the burette with the given solution of M/100 KMnO4 solution.

Rinse the pipette with the given ore solution and pipette out 20 mL of the given ore

solution in a titration flask.

Add 20 mL of dil. H2SO4.

Note the initial reading on the burette and start adding KMnO4 solution from the burette

into the titration flask till light pink colour appears.

Note the final reading on the burette and find the volume of KMnO4 solution used.

Repeat the titration to get three concordant readings

Observation Table

S.No. Burette reading Volume of KMnO4

used Initial Final

1

2

3

48

LMCHE010

Calculations:

Step 1 To calculate the molarity of ore solution

Let the volume of KMnO4 solution used be = x mL

Applying the molarity equation; i.e.

M1V1

n1 =

M2V2

n2

(Mohr salt) (KMnO4)

n1 = 5 n2 = 1 (from balanced chemical equation)

M1×20

5 =

1

100 × x

1

Molarity of iron in ore solution (M1) = x/400 M

Step 2 To calculate the strength of iron in ore solution

Since, Strength = Molarity × Molecular mass

Therefore strength of iron in ore solution = x/400 × 56

= y g/L

Step 3 To determine percentage of iron

Percentage of iron = y/20 x 100

Result: The percentage of iron is z%

Parameters: NA


Graphs/Plots: NA

Error Analysis: NA.

Cautions:

i. Don’t hold the pipette from the bulb.

ii. Don’t rinse the titration flask.

iii. Don’t blow off the last drop from the pipette.


1. M/100 KMnO4

2. Mohr salt solution (20g/L)

3. Dil. H2SO4

49

LMCHE010


Aim: To determine the percentage of iron in the given ferrous alloy by potassium permanganate

method.

Observation Table:

S.No. Burette reading Volume of KMnO4

used Initial Final

1

2

3

Calculations:


Error Analysis:


50

LMCHE010





Marks



20


learning outcomes

20


and Cleanliness

10


51

LMCHE010

EXPERIMENT NO. 10

Aim: To prepare phenol formaldehyde resin (bakelite).

Equipments to be used: Beaker, glass rod, funnel and filter paper

Chemicals used: Formaldehyde (40%), conc. H2SO4, distilled water, Glacial glacial acetic acid

and phenol.

Learning Objectives:

i. To understand the concept of condensation polymerization: It is the one which is

formed by combination of monomers accompanied by release of small molecules like

H2O and NH3.

ii. To study the preparation of Bakelite:

Bakelite formation involves the following reactions

Procedure:

Place 5 mL of glacial glacial acetic acid and 5 mL of 40% formaldehyde solution in a 500

mL beaker.

Add to it 2 grams of phenol with continuous stirring.

Add a few drops of conc. H2SO4 with constant stirring.

A pink solid plastic mass appears in the beaker.

Wash the solid mass with water and dry it in the folds of filter paper.

52

LMCHE010

Calculate the yield of the product.

Required Results:

The yield of bakelite resin is __________ g

Parameters: NA


Graphs/Plots: NA

Error Analysis: As the polymerization is taking place theoretical yield cannot be

calculated. The expected yield is 2g.

Cautions:

i. While adding conc. H2SO4, it is better to stay little away from the beaker, since the

reaction sometimes becomes vigorous.

ii. The reaction mixture should be stirred continuously.


1. 40% Formaldehyde

2. Phenol

3. Conc. H2SO4


53

LMCHE010


Aim: To prepare phenol formaldehyde resin (bakelite)

Observations:


Error Analysis:






Marks



20


learning outcomes

20


and Cleanliness

10


54

LMCHE010

EXPERIMENT NO. 11

Aim: To determine carbon monoxide content in emission from petrol vehicle.

Equipments to be used: Old newspaper, plastic bag, rubber band or twist tie, tape, scissors,

carbon monoxide detector and test automobile

Learning Objectives: (i) The purpose of the experiment is to determine the carbon monoxide

content.

(ii) Student will be able to get an idea about how carbon monoxide is detected at various

pollution control centers and how much is the toxicity level.

(iii) Student will be able to compare the level of carbon monoxide emission from various petrol

vehicles.


(I) Collection of the exhaust sample:

Cut a 2-3mm hole toward the bottom of the plastic bag. Using a permanent marker,

make a circle around the hole in the bag.

Place a small piece of tape over the hole and make sure it is secure. Fold the end of

the tape onto itself to create a small tab.

Wrap the outside of the tailpipe with newspaper without blocking the exhaust.

Compress the bag to remove all of the air from it and make sure the tape over the

sampling hole is secure before collecting the sample.

Hold the plastic bag against the newspaper that is wrapped around the tailpipe.

Start up the exhaust source while another person is ready to collect the sample of

exhaust and twist the bag closed once it fills with the car exhaust by tying a rubber

band.

(II) Testing the sample

Carefully pull back the tape covering the sampling hole and insert the carbon

monoxide detector into the bag.

Keep the detector inserted in the bag till it beeps.

Note the reading on the detector.

(III) Repeat the procedure for other sources.

55

LMCHE010

Observations:

Automobile source Carbon monoxide level (ppm)

Required Results: The level of carbon monoxide is highest in _______________ and

lowest in __________________.

Parameters: NA

Relationship: Between levels of carbon monoxide in exhaust from various petrol vehicles.

Graphs: NA

Error Analysis: NA

Cautions:

i. Exhaust should be collected carefully.

ii. Remember to cover the hole with the tape before collecting the exhaust.

iii. Keep you face away from the exhaust source.


1. Carbon monoxide detector

2. Automobile exhaust

3. Rubber band

4. Tape

5. Polythene bag

56

LMCHE010


Aim: To determine carbon monoxide content in emission from petrol vehicle.

Observation table:

Automobile source Carbon monoxide level (ppm)







Marks



20


learning outcomes

20


and Cleanliness

10


57

LMCHE010

EXPERIMENT NO. 12

Aim:To determine the amount of Dissolved Oxygen (DO) in the given water sample.

Equipments to be used: 300 mL BOD bottles, titration flask, pipette, burette, beakers, glass rod, funnel and burette stand

Chemicals used: Manganous sulphate, Alkali-iodide-azide, Concentrated H2SO4, Starch

solution, 0.025M Sodium thiosulphate and Potassium iodide

Learning Objectives:(i) To learn the importance of Dissolved oxygen as the measure of water

contamination.:The concentration of Dissolved Oxygen (DO) in natural water and wastewater

is a function of the temperature of the air and water, the degree of hardness of the water, and

the demand for oxygen in the body of water. The solubility of oxygen increases with decreasing

water temperature (oxygen solubility in water is inversely proportional to temperature). DO is

an important parameter in wastewater treatment processes, most notably when dealing with an

activated sludge system.

(ii) To make the students learn about the reactions taking place in this method:

Divalent manganese salt in solution is precipitated by alkali to manganese hydroxide

MnSO4 + 2KOH → Mn(OH)2 + K2SO4 In alkaline solution, dissolved oxygen is oxidized to form trivalent or higher valency hydroxide

2Mn(OH)2 + O2 → 2MnO(OH)2

Iodide ions reduce hydroxides to stable divalent ion by liberating equivalent amount of iodine.

MnO(OH)2 + 2KI + H2O → Mn(OH)2 + I2 + 2KOH

Thiosulphate solution is used with starch indicator, to titrate iodine.

I2 + 2S2O32-

→ S4O62-

+ 2I-

The Iodine is equivalent to dissolved oxygen present in the sample.

Indicator: Freshly prepared starch

End point: Blue to colourless


Fill a 300mL BOD bottle with the sample to be analyzed.

Pipette out 2 mL of manganous sulphate.

Pipette out 2 mL of alkali-iodide-azide.

Fix the stopper and invert the bottle several times to mix.

Allow the precipitates to settle in the solution to about half the volume of the bottle.

Invert the bottle several times to mix the precipitates back into the solution.

Allow the precipitates in the solution to settle to about half the volume of the bottle.

58

LMCHE010

After settling, add 1 mL concentrated sulphuric acid along the sides of the bottle, fix the

stopper and gently invert several times. Continue until the precipitate has dissolved back

into solution.

If a brown colour develops, dissolved oxygen is present in the sample. If no colour

develops or it is very faint, it may be appropriate to obtain another sample at this time to

ensure that there has not been an error in the sample preparation.

Titration

Take 200 mL of the above sample in a 500mL titration flask.

Fill the burette with standard sodium thiosulphate solution (0.025M)

Titrate the sample by adding sodium thiosulphate solution dropwise till solution of the

flask turns pale yellow.

Add 2-3 drops of starch solution and continue titrating dropwise until the disappearance

of the blue / purple colouration.

Note the volume used for thiosulphate used.

S.No. Burette reading

Volume used Initial Final

1

2

3

Calculations: When a 200mL sample is used, 1mL of sodium thiosulphate solution (0.025M)

is equivalent to 1mg/L Dissolved Oxygen in the sample.

(If 8.7mL of sodium thiosulphate was used, then DO of the sample is 8.7mg/L).

Result: The value of dissolved oxygen in the given sample of water was found to be mg/L.

Parameters: NA


Graphs/Plots: NA

Error Analysis: NA.

Cautions:

i. Always add concentrated H2SO4 in small amounts, along the sides of the bottle.

ii. End point should be noted carefully.

iii. Don’t blow off the last drop of the pipette.

59

LMCHE010


1. Waste water sample

2. Manganous sulphate

3. Alkali-iodide-azide

4. Conc. H2SO4

5. Starch solution

6. Potassium iodide solution

7. 0.025M Sodium thiosulphate

60

LMCHE010


Aim: To determine the amount of Dissolved Oxygen (DO) in the given water sample.

Observation Table:

S.No. Burette reading

Volume used Initial Final

1

2

3

Mean volume :________________ml

Calculations


Error Analysis:


61

LMCHE010





Marks



20


learning outcomes

20


and Cleanliness 10


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