chemistry practical 1 · experiment no -3 preparation of ... chemistry practical 1 lab manual 3...

CHEMISTRY PRACTICAL 1

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LAB MANUAL

CY OTI LS LER GE EVI MNU A- NE GR

AP LS UA RKI U

V

VIKAS PRE-UNIVERSITY COLLEGE

Experiment No -1 Parts of Bunsen Burner 03

Experiment No -2Study of glass works 04

Experiment No -3 Preparation of standard oxalic acid solution. 05

Experiment No -4Estimation of HCl using sodium carbonate 06

Experiment No - 5 Estimation of sodium hydroxide using oxalic acid 08

Experiment No - 6 Estimation of sodium hydroxide using HCl 10

Experiment No - 7Systematic Semi-micro qualitative analysis of a simple inorganic salt No-1 17




Experiment No -11Systematic semi-micro qualitative analysis of a simple inorganic salt-5 26



Experiment No -14Systematic Semi-micro qualitative analysis of a simple inorganic salt No-8 33

Index


LAB MANUAL



Experiment No -1 Parts of Bunsen Burner

Aim: To study the different parts of Bunsen Burner and nature of Bunsen flame.

Parts of Bunsen burner:

1)The Base

The base consists of a heavy metal with a horizontal side inlet.The side inlet tube is connected

through a rubber tubing to the source of combustible gas. The base has a brass nozzle

through which gas enters the burner tube.

2)The burner tube

It is long tube with two holes diametrically opposite to each other near the lower end.It is

screwed to the base with the nozzle at the centre and carries the air regulator.

3)The air regulator

It is a short metallic cylindrical sleeve that loosely fits on the lower end of the burner tube.It has

two holes diametrically opposite to each other.It can be rotated to regulate the supply of air into

the burner tube by partially or wholly opening or closing the air holes.

b) Working of the Bunsen Burner

The gas tap is opened and the burner is lighted.As the gas escapes through the nozzle ,there

is a fall of pressure and consequently air is sucked in through the air holes.The mixture of air

and the combustible gas burns at the top with a flame.Depending upon the supply of air,the

flame may be luminous or non-luminous.If the air hole is completely open, the maximum air is

sucked in and the gas burns with a pale blue non-luminous flame. If the air holes are

completely closed,the gas burns with a yellow, luminous flame.The non-luminous zone is the

hottest part of the flame.

Fig 1: Bunsen Burner


LAB MANUAL

3

Fig2: Zones of flame of Bunsen burner.

A small blue region at the base of the flame

A dark inner region of unburnt gases

A luminous region of incomplete combustion

A pale blue outer zone of complete combustion

Luminous flame

Fig2: Zones of flame of Bunsen burner.

A small blue region at the base of the flame

A dark inner region of unburnt gases

A pale blue outer zone of complete combustion

Non Luminous flame

3

2

1

Study of glass works

Cutting of a glass tube:

Select a glass tube.Hold it firmly and make a single deep scratch by means of a triangular file

without applying much pressure .Place the thumb on each side of the scratch at equal

distances from it.Gently press by givi ng a bending motion until it cuts.

Bending of a glass tube:

Place the tube in the hottest zone of the Bunsen flame and heat that portion where it is to be

bent keeping the tube rotating until it becomes soft and starts bending under its own

weight.Remove the tube from the flame and bend it slowly to a desired angle by pressing it

against a glazed tile to ensure coplanarity of the bend.Allow the bent tube to cool on the glazed

tile.

Drawing into capillary:

Heat the given tube in the hottest zone of the Bunsen flame holding it at both ends rotating the

tube gently until it becomes soft.Remove the tube from the flame and pull the ends apart slowly

until it becomes narrow in the middle.Cut the tube in the middle and make the jet uniform by

rubbing it with sand paper and by fire polishing.

Figures

Experiment No -2

4www.vikascollege.com


Making a scratch

Preparation of standard oxalic acid solution.

Aim: To prepare 100ml of 0.1M standard oxalic acid solution.

Principle:A solution whose concentration is exactly known is called Standard solution . A

standard solution of oxalic acid is used to determine the unknown concentration of an alkali

solution.The formula of hydrated oxalic acid is (COOH)2.2H2O and its molar mass is 126g. If

126g of oxalic acid is present in one litre of the solution,it is called as one molar solution.

To prepare one litre of 0.1M oxalic acid solu tion,we require 126/10=12.6g of hydrated oxalic

acid. Therefore for preparing 100ml of 0.1M oxalic acid solution we require 12.6×100/1000=

1.26g of hydrated oxalic acid. In general Molarity can be calculated using the formula

M=mass of the solute in grams × 1000/molar mass of the solute × volume of the solute to be

prepared in ml

Procedure:

Weigh an empty clean dry watch glass.Accurately weigh 1.26g of oxalic acid by placing

it on the watch glass.

Transfer oxalic acid carefully from the watch glass into a clean and dry 100ml of

standard flask using a funnel. Add a little amount of distilled water and swirl the flask

until the oxalic acid is completely dissolved. Add more distilled water with shaking and

make the solution upto the mark carefully by adding the last few ml dropwise. Stopper

the flask and shake it thoroughly to make the solution uniform throughout.

Calculate the molarity of the solution using the above mentioned formula.


LAB MANUAL

Experiment No -3

5

Estimation of HCl using sodium carbonate

Aim: Determination of concentration (s trength)of a given solution of dilute Hydrochloric acid by

titrating against standard solution of sodium carbonate.

Principle: Sodium carbonate reacts with hydrochloric acid as follows:

Na2CO3+2HCl →2NaCl +H 2O+CO 2

1 mole of Na2CO ≡3 2 mole of HCl

Acidity of the base Na2CO3 =2

Basicity of the acid=1

Aqueous solution of Sodium carbonate is a weak alkali while Hydrochloric acid is a strong

acid.Therefore methyl orange is used as the indicator during the titration.Methyl orange gives

yellow colour in alkaline solution while it turns red in acidic solutions. In neutral solutions it gives

an orange red colour.

Procedure:

Titration of standard Sodium carbonate solution against Hydrochloric Acid

Wash a burette with tap water,rinse it with distilled water and then rinse it with the given

hydrochloric acid care should be taken to see that no air bubbles are trapped in the

burette and its nozzle. Note the initial reading of the solution in the burette clamp the

Wash a 10cm3 pipette with tap water,rinse it with distilled water and then rinse it with the

standard sodium carbonate solution.

Pipette out exactly 10cm3 of standard sodium carbonate solution into a clean conical

flask.Add 2-3 drops of methyl orange indicator . The solution turns yellow. Place the

conical flask on a white glazed tile.Titrate the solution against hydrochloric acid taken in

the burette.Initially add small amounts of hydrochloric acid keeping the conical flask

swirled and then add the acid drop wise until the solution in the conical flask shows a

sharp change in colour from yellow to orange red. Now, note the final reading of the

Experiment No -4


solution in the burette.

Repeat the titration for concordant values.

Result: concentration of the given HCl solution =……….M

burette stand.


Tabulation and calculation:

In burette: HCl solution

In conical flask: Na2CO3 solution

Indicator: Methyl Orange

Colour Change: yellow to orange red.

Titration of 10cm 3 of Na2CO3 vs HCl

Trial No 1 2 3 F i nal Burette reading I n itial Burette reading Volume of HCl added in cm3

V2 =…….cm 3

Na2CO3 HCl

a M V1 1 1 = a M V 2 2 2

where, a1= Acidity of Na2CO3

a2=Basicity of HCl

M1=Molarity of Na 2CO 3

M2=Molarity of HCl

V1=Volume of Na 2CO 3

V2=Volume of HCl


LAB MANUAL

7

Strength of Hcl (M ) =2

a m v1 1 1

a v2 2

=

=_________M.

Estimation of sodium hydroxide using oxalic acid

Aim:

To determine the concentration of the given solution of sodium hydroxide by titrating against

standard solution of oxalic acid.

Principle:

Sodium hydroxide reacts with oxalic acid as follows:

COOH COONa

+2NaOH→ +2H 2O

COONa

1 mole of oxalic acid ≡2 mole of NaOH

The molarity of the solution can be can be calculated using the formula,

a M V1 1 1=a M V 2 2 2

Where a M V1 1 1 are respectively the basicity, molarity and volume of the acid while a 2 ,M2 and V2

are the acidity , molarity and the volume of the base.

Molecular mass of oxalic acid crystals , H C O2 2 4 .2H2O is 126 g mol-1

Molecular mass of NaOH = 40 gmol -1 .

A known volume of sodium hydroxide is titrated against standard oxalic acid.Oxalic acid is a

weak acid while sodium hydroxide is a strong base.Therefore, phenolphthalein is used as the

indicator. Phenolphthalein turns pink in alkaline solution while it remains colourless in neutral

and acidic solutions.The end point is reached when the last drop of oxalic acid added from the

burette turns the colour of NaOH solution in the conical flask from pink to colourless.

Procedure:

Wash the burette with tap water,rinse it with distilled water and then rinse it with

the standard oxalic acid solution.Then fill the burette with the standard oxalic

acid solution. Care should be taken to see that there is no air bubbles trapped

inside the burette and its nozzle.Note the initial reading of the burette.Clamp the

burette to the burette stand.

Experiment No - 5


COOH


Wash a 10cm3 pipette with tap water,rinse it with distilled water and then rinse it

with the given Sodium hydroxide solution. Pipette out exactly 10cm3 of the

Sodium hydroxide solution.Add 2-3 drop s of phenolphthalein indicator. The

solution turns pink.Place the conical flas k on a glazed tile. Add oxalic acid from

the burette to the conical flask.Keep the conical flask swirling after each addition

of oxalic acid.Add oxalic acid in small amount initially and then dropwise. Near

the end point the pink colour fades away. Continue to add the acid drop at a

time,swirling the conical flask until the last drop added turns the solution from

light pink to colourless. Note the final reading of the burette.

Result: Concentration of NaOH solution = …………M


LAB MANUAL

9

Tabulation and Calculation:

In burette: Oxalic Acid solution

In conical flask: NaOH solution

Indicator: phenolphthalein

Colour Change: Pink to colourless

Titration of 10cm 3 of NaOH vs Oxalic acid

Trial No 1 2 3 F i nal Burette reading

I n itial Burette reading

Volume of Oxalic acid

added in cm 3

V1 =…….cm3

Oxalic acid NaOH

a M V1 1 1 = a M V2 2 2

=

=…………M

10

Estimation of sodium hydroxide using HCl

Aim:

To estimate the concentration of NaOH using 0.1M. HCl.

Experiment No - 6

Principle :

A known volume NaOH solution is titrated against standard HCl solution using phenolpthalein.

Molarity of solution is calculated using the formula a M V = a M V1 1 1 2 2 2

NaOH + HCl NaCl + H 02

Where a and a are the acidity and basicity of the base and acid respectively.1 2

M and M are the molarities. V and V are the volume of base and acid respectively.1 2 1 2

Procedure :

A clean burette is washed with the water and rinsed with 0.1 M HCl solution. It is then filled with 3HCl solution. Initial burette reading is noted. A 10cm of cleaned pepette is washed with

3H 0 and rinsed with NaOH solution. Exactly 10cm of NaOH solution is pipetted to a cleaned2

conical flask. 2 drops of phenolphthalein is added, the solution turns pink.

The solution in conical flask is titrated against HCl taken in the burette. At the end point pinkcolour of solution changes to colourless. Final burette reading is noted. The titration is repeatedto get agreeing values.

Result :

concentration of NaOH solution = _________________M




LAB MANUAL

11

Tabulation and calculation

3Titration of 10cm of NaOH using HCl.In burette - HCl solutionIn conical glass - NaOH solutionIndication - phenolphthaleinColour Change - pink to colourless

Trial No. 1 2 3

Finalburettereading

Inititalburettereading

Volume ofHCl added in

3(cm )

3V = cm2

a = acidity of NaOH1

a = basicity of HCl2

M = Molarity of NaOH1

M = Molarity of HCl 2

V = Volume of NaOH1

V = Volume of HCl 2

NaOH HCl

a M V a M V1 1 1 = 2 2 2

M1 = a2 M2 V2

a1 v1

M1 =

M1 = _______________ M.

Strength of NaOH,

Inorganic salt analysis

Aim: Systematic semi-micro qualitative analysis of a simple inorganic salt.

Experiment Observation Inference

1.The given salt is observed in the presence of light.

White crystalline Cu2+, Fe3+, Mn2+, Co2+, Ni2+, may be absent in salt.

Light pink crystalline Mn 2+ salts may be present.

White amorphous CO32-,HCO3

-,or S2- may be present 2.Solubility in water: A pinch of salt+ 10 drops of water and shaken.

Soluble No inference possible Insoluble Salts of Na+ ,K+ or NH4

+ may be absent.

DETECTION OF ACID RADICALS: (ANION)

DETECTION OF FIRST GROUP ACID RADICAL: (CO32-)

A pinch of salt +dil.H 2SO4

The gas liberated is passed into the test tube containing lime water.

Brisk effervescence I group acid radicals are present

Lime water turns milky Carbonate is present and confirmed

No brisk effervescence 1 group acid radicals are absent

DETECTION OF SECOND GROUP ACID RADICALS (Cl -,Br-,NO3-)

A pinch of salt+Conc.H 2SO4 Colourless fuming gas is evolved, which gives dense white fumes with a glass rod dipped in NH 4OH

II group acid radicals is present Chloride may be present

Reddish brown fumes and the solution turns brown

II group acid radical is present Bromide may be present

No characteristic observation Chloride and Bromide are absent

Above solution+Copper turnings. Heated strongly.

Reddish brown fumes and the solution turns blue No reddish brown gas

IIgroup acid radicals is present Nitrate may be present Nitrate is absent II group acid radicals absent.

12



a)Barium Chloride test: Clear solution of the salt in dil.HCl+2drops of Barium chloride solution.

A white precipitate insoluble in excess of dil.HCl

III group acid radical is present Sulphate is present and confirmed

b)Lead acetate test: Clear solution of the salt in water+Acetic acid+Lead acetate solution.

A white precipitate soluble in ammonium acetate solution

Sulphate is present and confirmed.

CONFIRMATORY TEST FOR CHLORIDE (Cl -)

1.Silver Nitrate test: Clear salt solution in dilute Nitric acid+3 drops of silver nitrate solution

A curdy white precipitate soluble in excess of ammonium hydroxide

Chloride is confirmed.

2.Chromyl Chloride test: A pinch of salt +potassium dichromate crystals +few drops of conc.H 2SO4,mixture is heated The vapours are dissolved in water. To the yellow solution+3 drops of NH4OH+3 drops of acetic acid+2 drops of lead acetate solution

Reddish brown vapours of Chromyl Chloride are evolved Yellow solution. Yellow precipitate


CONFIRMATORY TEST FOR BROMIDE (Br -)

1.Silver Nitrate test: Clear salt solution in dilute nitric acid+ boil & cool 3 drops of silver nitrate solution.

A pale yellow precipitate partially soluble in excess of ammonium hydroxide

Bromide is confirmed

2.Orange globule test: Clear salt solution in water+ 3 drops of carbon tetrachloride + Chlorine water, shaken well.

Orange brown globule separates out


13

DETECTION OF THIRD GROUP ACID RADICAL (SO42-)


LAB MANUAL

Brown ring test: 3 drops of clear salt solution in dil.H2SO4+3 drops of freshly saturated solution of Mohr’s salt+conc.H 2SO4 is added carefully along the sides of the test tube

A brown ring is formed at the junction of two liquids

Nitrate is confirmed

DETECTION OF BASIC RADICALS (CATIONS):

TEST FOR AMMONIUM (NH 4+ ) RADICAL: (ZERO GROUP ANALYSIS)

Action of NaOH: A pinch of the salt is heated with 5 drops of sodium hydroxide

A Pungent smell of ammonia which gives dense white fumes with a glass rod dipped in conc.HCl

NH4

+ may be present

No pungent smell of ammonia

NH4+ is absent

CONFIRMATORY TEST FOR AMMONIUM (NH 4+ ) RADICAL:

Nessler’s reagent test: One drop of salt solution in water+3 drops of Nessler’s reagent

Brown precipitate is formed

NH4

+ is confirmed

PREPARATION OF ORIGINAL SOLUTION:

The given salt is taken in a test tube and it is dissolved in minimum amount of water or dil. HCl.

14

CONFIRMATORY TEST FOR NITRATE(NO 3-):



DETECTION OF GROUP OF CATIONS:

Group I: 1cm3 of OS + 1cm3 of dil.HCl in a test tube

No precipitate I group cations are absent

Group II: 1cm3 of OS + 1cm 3 of dil.HCl+H 2S solution is added

No precipitate II group cations are absent

Group III: 1cm3 of OS +2cm 3 of NH4Cl solution +NH 4OH solution in excess

A Gelatinous white precipitate Al3+ may be present

No precipitate III group cations are absent

Group IV: 1cm3 of OS +2Cm 3 of NH4Cl solution +NH 4OH solution in excess + H2S solution is added

A flesh coloured precipitate Mn 2+ may be present

No precipitate IV group cations are absent

Group V: 1cm3 of OS +2Cm3 of NH4Cl solution +NH 4OH solution in excess +(NH )4 2CO3 Solution

A white precipitate Ba2+, Sr2+, or ca2+ may be present

No precipitate V group cations are absent

Confirmatory test for Aluminium(Al 3+ )

a)Sodium hydroxide test: 1cm 3 of original solution+NaOH solution dropwise Above solution is treated with NH4Cl solution.

Gelatinous white precipitate soluble in excess of NaOH White gelatinous precipitate reappears

Al3+ is confirmed

b)Lake test: Original solution+blue litmus solution +NH 4OH drop wise along the sides of the test tube

Blue precipitate floating in the colourless solution

Al3+ is confirmed

Confirmatory test for Manganous (Mn2+ )

a)Sodium hydroxide test: 1cm 3 of original solution+NaOH solution dropwise.

White precipitate formed is insoluble in excess of NaOH and turns brown on exposure to air.

Mn2+ is confirmed

b) Lead dioxide test: 1cm3 of OS +conc.HNO 3+a pinch of lead dioxide,heated strongly and diluted with water.

Supernatant layer is pink in colour.

Mn2+ is confirmed

15


LAB MANUAL

Confirmatory test for V group cations:

a)Potassium chromate test: 1cm3 of original solution+acetic + acid +potassium chromate solution

Yellow precipitate Ba 2+ is confirmed

No yellow precipitate Ba2+ is absent

b)Ammonium sulphate test: 1cm 3 of original solution+ammonium sulphate solution,warm.

White precipitate Sr2+ is confirmed

No white precipitate Sr2+ is absent

c)Ammonium oxalate test: 1Cm3 of original solution+5 drops of NH 4OH +Ammonium oxalate solution.

White precipitate Ca2+ is confirmed

Flame test: A pinch of salt +few drops conc.HCl and made into a paste. The paste is held to the flame with the help of a platinum wire.

a) Apple green colour is imparted to the flame b) Crimson red colour is imparted to the flame c) Brick red colour is imparted to the flame

Ba2+ is confirmed Sr2+ is confirmed Ca2+ is confirmed

Analysis of VI group basic radical:

Confirmatory test for Magnesium (Mg2+ ) 1) Disodium hydrogen phosphate test: 1cm3 of original solution+2cm of NH OH+5 4

drops of disodium hydrogen phosphate.The side of the test tube is scratched with glass rod.

White crystalline precipitate

Mg2+ is confirmed.

2) Sodium hydroxide test: 1cm3 of original solution+NaOH Solution.

White precipitate insoluble in NaOH solution

Mg2+ is confirmed.

Report: The given inorganic salt contains,

Anion is ……………………(……..).It belongs to group……….

Cation is…………………….(…….).It belongs to group……….

Hence the given salt is…………………………(……….)

16

3



Aim: Systematic Semi-micro qualitative analysis of a simple inorganic salt No-1

Experiment Observation Inference 1.Colour &Appearance The given salt is observed in the presence of light

White crystalline

Cu2+, Fe3+, Mn2+, Co2+, Ni2+, may be absent.

2.Solubility in water: A pinch of salt+10 drops of water and shaken well

Soluble

No inference possible


DETECTION OF FIRST GROUP ACID RADICAL: (CO 32-)

A pinch of salt+dil.H 2SO4 No brisk effervescence I group acid radicals absent


A pinch of salt+conc.H 2SO4 Colourless fuming gas is evolved, which gives dense white fumes with a glass rod dipped in NH 4OH

II group acid radical is present Chloride may be present

CONFIRMATORY TEST FOR CHLORIDE(Cl -)







Experiment No - 7

17


LAB MANUAL

DETECTION OF BASIC RADICALS(CATIONS)




NH4

+ may be present




NH4

+ is confirmed

Result: The given inorganic salt contains

Anion is Chloride(Cl -). It belongs to II group

Cation is Ammonium(NH 4+ ).It belongs to 0 th group

Hence the given salt is Ammonium Chloride(NH 4Cl).

18





White crystalline



Soluble





DETECTION OF SECOND GROUP ACID RADICAL: (Cl -,Br-,NO3-)

A pinch of salt +conc.H 2SO4 No characteristic observation Chloride and Bromide are absent

Above solution+Copper turnings.Heated strongly.

No reddish brown gas Nitrate is absent II group acid radicals are absent.

DETECTION OF THIRD GROUP ACID RADICAL(SO 42-)







Experiment No - 8

19


LAB MANUAL

DETECTION OF BASIC RADICALS (CATIONS)




NH4+ is absent.


The given salt is taken in a clean test tube and it is dissolved in minimum amount of water.

DETECTION OF THE GROUP OF CATIONS:

Group I: 1cm3 of OS + 1cm 3 of dil.HCl in a test tube




Group III: 1cm3 of OS +2Cm 3 of NH4Cl solution +NH 4OH solution in excess

A Gelatinous white precipitate III group cation is present Al3+ may be present

Confirmatory test for Aluminium(Al3+ )

a)Sodium hydroxide test: 1Cm3 of original solution+NaOH solution dropwise Above solution is treated with NH4Cl solution.

Gelatinous white precipitate soluble in excess of NaOH White gelatinous precipitate reappears

Al3+ is confirmed

b)Lake test: Original solution+blue litmus solution +NH 4OH drop wise along the sides of the test tube

Blue precipitate floating in the colourless solution

Al3+ is confirmed

Result:

The given inorganic salt contains

Anion is Sulphate (SO 42-) It belongs to Group III

Cation is Aluminium(Al3+ )It belongs to Group III

Hence the given salt is Aluminium Sulphate Al 2(SO )4 3

20




Experiment Observation Inference 1.Colour &Appearance The given sal tis observed in the presence of light

White crystalline



Soluble















Experiment No - 9

21


LAB MANUAL

DETECTION OF BASIC RADICALS (CATIONS)




NH4

+ is absent.


The given salt is taken in a clean test tube and it is dissolved in minimum amount of water.








Group IV: 1cm3 of OS +2Cm 3 of NH4Cl solution +NH 4OH solution in excess+H 2S solution is added


Group V: 1cm3 of OS +2Cm 3 of NH4Cl solution +NH 4OH solution in excess +(NH )4 2CO3 Solution

A white precipitate

V group cations is present Ba2+ ,Sr2+ ,or ca2+ may be present


a)Potassium chromate test: 1cm3 of original solution+acetic acid + potassium chromate solution

Yellow precipitate

Ba2+ is confirmed


Apple green colour is imparted to the flame

Ba2+ is confirmed

22




Anion is Chloride(Cl -). It belongs to group II.

Cation is Barium (Ba2+ ).It belongs to groupV.

Hence the given salt is Barium Chloride(BaCl2)

23


LAB MANUAL



White amorphous

CO 3

2-,HCO3- ,Or S2- may be

present. 2.Solubility in water: A pinch of salt+10 drops of water and shaken well

Insoluble

Salts of Na+ ,K+ , or NH4

+ may be absent.





Brisk effervescence Lime water turns milky

I group acid radicals are present Carbonate is present and confirmed





NH4

+ is absent.


The given salt is taken in a clean test tube and it is dissolved in minimum amount of dil.HCl






Experiment No - 10

24








A white precipitate



a)Potassium chromate test: 1Cm3 of original solution+potassium chromate solution

No yellow precipitate

Ba2+ is absent

b)Ammonium sulphate test: 1Cm3 of original solution+ammonium sulphate solution,warm.

No white precipitate

Sr2+ is absent

c)Ammonium oxalate test: 1Cm3 of original solution+5 drops of NH 4OH +Ammonium oxalate solution.

White precipitate

Ca2+ is confirmed


Brick red colour is imparted to the flame

Ca2+ is confirmed

Report:

Anion is Carbonate (CO32-).It belongs to group I.

Cation is Calcium (Ca2+ ).It belongs to groupV.

Hence the given salt is Calcium Carbonate (CaCO3).

25


LAB MANUAL

Aim: Systematic semi-micro qualitative analysis of a simple inorganic salt-5


White crystalline



Soluble





DETECTION OF SECOND GROUP ACID RADICAL: (Cl -,Br-,NO3-)

A pinch of salt +conc.H 2SO4 No characteristic observation Chloride and Bromide are absent

Above solution+Copper turnings.Heated strongly.

No reddish brown gas Nitrate is absent II group acid radicals are absent.

DETECTION OF THIRD GROUP ACID RADICAL(SO 42-)







Experiment No -11

26







NH4

+ is absent.


The given salt is taken in a clean test tube and it is dissolved in minimum amount of Water










Group V: 1cm3 of OS +2Cm 3 of NH4Cl solution +NH 4OH solution in excess +(NH )4 2CO 3

Solution

No precipitate

V group cations are absent


Confirmatory test for Magnesium (Mg2+ ) 1)Disodium hydrogen phosphate test: 1Cm3 of original solution+2Cm3 of NH4OH+5 drops of disodium hydrogen phosphate.The side of the test tube is scratched with glass rod.


Mg2+ is confirmed.

2) Sodium hydroxide test: 1Cm3 of original solution+NaOH Solution.


Mg2+ is confirmed.

27


LAB MANUAL


Anion is Sulphate(SO42-).It belongs to groupIII

Cation isMagnesium(Mg 2+ ).It belongs to groupVI.

Hence the given salt isMagnesium Sulphate (MgSO 4.)

28





White crystalline



Soluble






A pinch of salt+conc.H 2SO4 Reddish brown fumes and the solution turns brown

II group acid radical is present Bromide may be present

CONFIRMATORY TEST FOR BROMIDE (Br -)

1.Silver Nitrate test: Clear salt solution in dilute nitric acid+3 drops of silver nitrate solution.

A pale yellow precipitate partially soluble in excess of ammonium hydroxide


2.Orange globule test: Clear salt solution in water+3 drops of carbon tetrachloride+Chlorine water,shaken well.

Orange brown globule separates out




Experiment No -12

29


LAB MANUAL



NH4

+ may be present




NH4

+ is confirmed


Anion is Bromide(Br -). It belongs to II group

Cation is Ammonium(NH 4+ ).It belongs to 0 th group

Hence the given salt is Ammonium Bromide(NH 4Br).

30





White amorphous

CO 3

2-,HCO3- ,Or S2- may be

present. 2.Solubility in water: A pinch of salt+10 drops of water and shaken well

Insoluble

Salts of Na+ ,K+ , or NH4

+ may be absent.





Brisk effervescence Lime water turns milky

I group acid radicals are present Carbonate is present and confirmed





NH4

+ is absent.


The given salt is taken in a clean test tube and it is dissolved in minimum amount of dil.HCl






Experiment No -13

31


LAB MANUAL






No precipitate

V group cations are absent


Confirmatory test for Magnesium (Mg2+ ) 1)Disodium hydrogen phosphate test: 1cm 3 of original solution+2cm3 of NH OH+5 4

drops of disodium hydrogen phosphate.The side of the test tube is scratched with glass rod.


Mg2+ is confirmed.

2) Sodium hydroxide test: 1cm 3 of original solution+NaOH Solution.


Mg2+ is confirmed.


Anion is Carbonate (CO32-). It belongs to groupI

Cation isMagnesium(Mg 2+ ).It belongs to groupVI.

Hence the given salt isMagnesium Carbonate(MgCO 3)

32





White crystalline



Soluble















Experiment No -14

33


LAB MANUAL





NH4

+ is absent.


The given salt is taken in a clean test tube and it is dissolved in minimum amount of Water











A white precipitate



a)Potassium chromate test: 1Cm3 of original solution+potassium chromate solution

No yellow precipitate

Ba2+ is absent

b)Ammonium sulphate test: 1Cm3 of original solution+ammonium sulphate solution,warm.

White precipitate

Sr2+ is confirmed

34




Crimson red colour is imparted to the flame

Sr2+ is confirmed


Anion is Chloride(Cl -). It belongs to groupII

Cation is Strontium (Sr2+ ).It belongs to groupV

Hence the given salt is Strontium Chloride(SrCl 2)

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LAB MANUAL

1. Do not enter the laboratory when an instructor/lab assistant is not present or the lab door is closed. Finish your lab work on time to clean up before the end of the scheduled lab period.

2. Perform only authorized experiments. Parents, Visitors are not permitted to be with you while you do your lab work.

3. Wear personal protective equipment (PPE) at all times in the chemistry laboratory including when cleaning up following an experiment.

4. Shoes which offer reasonable protection will be worn while in the laboratory. Shoes must cover the entire foot, including the toes, the top of the foot, and the heel.

5. Hair that is longer than shoulder-length must be tied back at all times.

6. Eating, drinking, mouth rinsing, applying cosmetics or lip balm or handling contact lenses is prohibited in the lab areas. No chewing gum is allowed.

7. Be considerate of others working in the laboratory. Do not distract others while conducting experiments or accomplishing lab activities. When finished with equipment or materials to be shared with others, make the equipment or materials available to others as quickly as possible.

8. Before leaving the lab, clean all equipment, glassware and the work area you have been using. Return equipment and glassware to their proper places in the laboratory.

9. Know the location and proper use of safety equipment in the laboratory.

10. Immediately notify the lab instructor of chemical spills, broken glass or other hazards. Do not attempt to clean up such mishaps/materials by yourself without first alerting your instructor/lab supervisor.

11. Immediately notify the instructor/lab supervisor of any accidents, injuries, or situations in which exposure to human blood or other potentially infectious materials in the laboratory has occurred, regardless of how minor they may appear to be.

12. You may be exposed to potentially hazardous materials in the process of completing your required laboratory activities. Persons with specific health concerns such as wearers of contact lenses, persons with known hypersensitivities, etc. should consult their personal physician for advisement about potential risks before continuing in the course.

SAFETY PROCEDURE IN LAB



NOTE


LAB MANUAL

SUCCESS GUARANTEED ONLY AT VIKAS

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