lab manual msc. chemistry

8/13/2019 Lab manual MSc. Chemistry

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Experiment Observation

Colour White/Yellow/Brown etc.

State Solid/Liquid

Odour FruityPungent

Carbolic/Phenolic

Bitter Almond

Kerosene

Aromatic Odour

Ignition Test Luminous, Sooty Flame

Non-Luminous, Non-Sooty

Darkens, Chars with smell of burnt sugar

Melts, Vapourises, smells like NH3

Green flame [on a copper wire]

Tests for Unsaturation

1) Bromine Test

0.2g/0.2ml of compound in 2 cm Ccl4 + 2 % Br in Ccl4 (Drop-

Wise) (Blow across the mouth of the test tube) Decolourisation, No evolution of HBr

Decolourisation, Evolution of HBr

No Decolourisation

2) Baeyers Test:0.2g/0.2ml of compound in H2O/acetone + Cold KMnO4

soln. (Drop Wise) Decolourisation

No Decolourisation

Litmus Test: Moist Litmus Paper in Compound Blue to red


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Litmus Test: Moist Litmus Paper in Compound Blue to red

Inference

EstersVolatile Acids

Phenolic Compounds

Nitrobenzene/Benzaldehyde

Aromatic Hydrocarbons

Aromatic Compounds

Aromatic (highly unsaturated)

Saturated Aliphatic

Sugars

Amides/Urea

Halogenated Compound

Unsaturated Compound

Unsaturated Reactive Compound

Saturated/Unreactive Aromatic Compound

Unsaturated or presence of easily oxidisable groups

Saturated/Unreactive Aromatic Compound

Acidic


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Inference

Nitrogen Present

Sulphur Present

Halogen Present

Halogen Present


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Experiment Observation Inference

CARBOHYDRATES:

1) Ignition Test Non Luminous, Smell of Burnt Sugar, Black Res Carbohydrate

2) Dehydration: 0.2g (dry)+ conc. H2SO4, warm Charred, turns black Carbohydrate

3) Molisch's Test:

0.1g in 2ml water + 2 drops -naphthol in Alcohol +2ml conc. H2SO4 (Slowly onsides of tube) Violet/Purple Colour @ Interface Carbohydrate

4) Seliwanoff's Test: 0.1g + 2-3ml 0.1% Resorcinol in water + conc. H2SO4

Carefully without mixing Red/Orange at junction of two layers Carbohydrate

5) Fehling's Test:

4ml Fehling's soln (2ml A + 2ml B) + 0.1g in 2ml water. Boil 2 mins. Red ppt. Reducing Sugar


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Amides

1) Hydrolysis: Boil 0.5g + 3ml 10% NaOH

Smell of NH3, dense white fumes with conc.

HCl, gas-> red litmus to blue

Primary amide

[unsubstituted]

Divide above soln. into 2 parts

a)Cool 1 part, acidify with conc.HCl White ppt

Amide of aromatic

acid

b) Other part, evaporate to dryness on china dish + 2-3ml Alcohol + conc. H2SO4

& Warm. Cool and pour into water. Fruity Odour Amide

2) 3ml HgCl2soln. + NaOH drop wise til yellow ppt. of HgO is formed. + 0.2g

compound. Warm On Heating, yellow ppt. HgO dissolves. Amide

2RCONH2+ HgO (RCONH)2Hg + H2O

Pass H2S through soln. Black ppt. Amide

3) Nitrous Acid test:

0.2g in 1ml dil. HCl + 1ml of cold fresh NaNO2 soln. Brisk Effervescence of Nitrogen Primary Amide

4) Hydroxamic acid Test:

0.1g + 1ml hydroxylamine hydrochloride in propylene glycol + 4-5 drops 10%

NaOH soln. Boil, cool, acidify with HCl + 1-2 drops of FeCl 3 Burgundy/Magenta Colour Amide


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Experiment

Urea

1) 0.2g + 5ml 20% NaOH2) Nitrous Acid Test:

0.2g+ 2-3ml dil. HCl + 3ml 5% NaNO2

3) Biuret Test:

0.5g in dry t.t + heat above M.P. 1-2min .. dissolve above residue + few ml 10%

NaOH soln. Cool+ 1 drop of CuSO4

2 CO(NH2)2 H2N-CO-NH-CO-NH2+ NH3

4) Urea Nitrate Test:

0.5g+ 3ml water+ 1ml of conc. HNO3

(NH2)2CO (aq) + HNO3(aq) (NH2)2COHNO3(s)


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Observation Inference

Pungent gas with smell of NH3. Gas-> Blue

litmus to red Urea

Brisk effervescene of N2 and CO2 Urea

Purple Colour Urea

White Crystals Urea


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AMINES:

1) Carbyl amine test:

compound in alcohol + 2ml of 10% alc. KOH + CHCl3 Offensive Odour Primary Amine

destroy the isocyanide adding dil. HCl or dil. NaOH

2)Benzoylation

0.2g+ 2ml benzoyl chloride+ 2ml 10% NaOH, warm on water bath, pour into

water Solid Derivative Primary/Secondary Amine

or 0.2g+ 2ml benzoyl chloride + 5% NaOH in a conical flask & Cork shake until

solid separates

Schotten-Baumann Reaction:

3) Acetylation

0.2g+ Acetyl Chloride/ water+acetic anhydride. Drop Wise. Warm on water

bath & pour into water, Stir White solid Primary/Secondary Amine

RNH2 + ClOCCH3 ----> RNHOCCH3 -HCl

R2 NH + ClOCCH3 ----> R2 NOCCH3 - HCl


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4) Action of Nitrous Acid

sub. + 5ml of (1:1 HCl), warm, if insoluble. Cool to 0degC in ice, add cooled soln.

of NaNO2 slowly. Brisk evolution of N2 gas Alkyl primary amine

Little/no evolution of gas, clear soln. Aromatic Primary Amine

no evolution of gas but yellow oil

separates slowly Secondary Amine

colored soln. Tert. Amine

a) Diazotization:1 part of above solution + -naphthol in NaOH soln Red Dye Aromatic Primary Amine


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Experiment

Carboxylic Acids:

1) Reaction with NaHCO3

substance+sat.aq soln. of NaHCO3. If no rxn takes place. Warm

CH3COOH + NaHCO3 CH3COONa

++ CO2+ H2O

2) Litmus Test

Compound in water. Dip Litmus

3) Ester Formation

0.5g+ 2ml Ethanol + 3-4 drops conc. H2SO4, heat for 2min., cool and pour into

beaker containing Na2CO3 soln.

RCO2H + R'OH ---> RCO2R' + H2O

4)Amide Formation

compound+ Pcl5 on watch glass/mortar, mix well and add liquor ammoniaRCOOH

SOCl2

R C

O

Cl SO2 HCl+ +

RCOOH +3 3 H3PO

3PCl3

R C

O

Cl

RCOOH R C

O

Cl +PCl

5

POCl3+HCl


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Effervescence of CO2 Carboxylic acid

Blue to red Acidic substance

Fruity Odour of an ester Carboxylic Acid

white solid Carboxylic Acid


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Experiment

Phenols:

1) FeCl3 test:

0.05g in 5ml water. Add 2 drops in neutral, alc FeCl3 soln.3ArOH + FeCl3 > Fe(OAr)3 + 3HCl

2) Libermann's Rxn:

0.5g compound+ pinch of NaNO2 in testube, warm, cool+ few drops of conc.

H2SO4+ Heat, cool pour into water. Add xs dil. NaOH

3) Phthalein Fusion Test

0.2g + 0.2g phthalic anhyride+ 2-3drops of con. H2so4 in tt. Heat, cool add few

drops of NaOH soln.

C6H5-OH + C6H4(CO)2O in H2SO4---> (p-HO-C6H5)2-C-O-C=O

4) Aniline + conc. HCl+ water, cool to 0degC + NaNO2 + 10% NaOH

5) Bromine Water test

0.1g/2drops in H2O+ xs Bromine water drop wise


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Violet/blue/red/orange/green Phenol

Intense green->pale red in h20--> blue/green

adding NaOH Phenol

pink/red/blue/purple/green Phenol

Bright color Phenol

Brown colour of bromine is discharged and

white solid separates Phenol


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Aldehydes and Ketones

1) Substance + 2,4 DNPH {di-nitro-phenyl hydrazine) reagent, shake yellow/orange ppt. Ald/ket

2) Substance+ sat. NaHSO3 soln. Shake 2-3mins White solid Ald/ket

3) Schiff's Test: Compound+ Schiff's reagent, shake Pink color at room temp. Aldehyde

Pink color on heating Ketone


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4) Tollen's Test:

1ml tollen's reagent+ 0.2g/2-3 drops compound in alcohol. Warm over

waterbath. Prepare Tollen's Reagent- AgNO3 + few drops of NaOH. Dissolve

brown ppt. by adding NH4OH dropwise Silver Mirror/ Grey ppt. Aldehyde

no silver mirror ketone

[Ag(NH3)2]+(aq) + e

- Ag (s) + 2 NH3(aq)

RCHO (aq) + 3 OH- RCOO

-+ 2 H2O + 2 e

5) Fehling's Test

substance + Fehling A+B equally + heat red/green/brown ppt. aldehyde

no.ppt ketone

6)Nitroprusside test:

substance in water + alcohol + 1% Sodium Nitroprusside soln. + 10% NaOH (3-

4drops). Acidify with acetic acid wine red/yellow, turns purple to red ketone7)Iodoform Test:

0.1g+ 1ml 5% NaOH+ Iodine soln. til colour persists. Shake soln., warm +5%

NaOH til colourless yellow crystals of iodoform with sweet smell methyl ketone


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Alcohols:

1) Sodium Test

few drops of compound in dry fusion tube + small piece of Na Metal Evolution of bubbles/effervescence Alcohol

2)Esterification: compound+glacial acetic acid+ few drop conc. H2SO4. Heat,

pour into water fruity odour Alcohol

3)Xanthate Test

one pellet KOH+Substance, heat,cool add CS2 pale yellow ppt. xanthate salts Alcohol

ROH + CS2+ KOH ROCS2K + H2O

4)Substance in water+ Ammonium Vanadate (NH4VO4) 2 drops + 8-

hydroxyquinoline

Green ppt. turn red on shaking. Red color in

benzene layer Alcohol

Esters:

1) Hydroxamic Acid Test:

0.1g + 1ml hydroxylamine hydrochloride in alcohol+ 20% NaOH soln. til a lkaline.

Boil, cool, acidify with HCl + 2-3 drops of FeCl3 Ester

2) Phenolphthalein test:

0.5ml compound + 2ml alcohol+ 2drops of 10% NaOH+ 1-2 drops

Phenolphthalein. Boil on water bath. Pink colour fades away Ester

3) Saponification:

0.5g+ 5ml 20% NaOH in china dish. Boil till ester disappears(15-30min) Cool,

acidify with conc. HCl White Solid

Ester of

aromatic acid

RCOOR' + NaOH ----> R COONa+ + R'OH

4)1ml+0.5g 3,5 dinitrobenzoic acid+ 3-4drops conc. H2SO4. Heat gently for 5

min. Add carefully to 10ml water. Add NaOH till alkaline

Crystalline solid(3,5 dinitrobenzoate of

alcohol component of ester) Ester


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Experiment

Halogenated Hydrocarbons

1) Beilstein test:

Heat the Cu wire til no green color is imparted to flame. Dip wire in compoundand heat in non-luminous flame

2) Alcoholic AgNO3 test

0.2g+ 3ml alcoholic silver nitrate and boil

3)KMnO4 test:

0.5g sub+ 2ml NaOH+ 2ml 2% KMnO4. Boil

4)Bromine test:

0.2g +2ml CCl4 + Br2 in CCl4 dropwise

5) 0.1g+2 drops CCl4+ 2 drops formalin+ 2ml conc. H2SO4. Shake.


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green colored flame halogenated compound

Curdy white/yellow ppt. Halogen present on side chain

No ppt.

Halogen directly attached to

aromatic ring

Pink color discharged Halogen attached to side chain

No decolorisation

Halogen attached to aromatic

ring

Decolorisation of bromine Unsaturated Halogenated

No decolourisation of bromine Saturated/aromatic halogenatedPink/red/bluish red aryl halide

Amber/brown/yellow alkyl halide


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Anilides:

1)Isocyanide rxn:

0.2g + 3ml alcoholic NaOH soln. + 1ml chloroform. Heat 1 min. Foul smell of isocyanide Anilide or amine not an amide

no smell

Anilide and primary amine

absent

2)Hydrolysis

0.5g+ 10ml 20% NaOH, boil 10min. Cool, acidify with conc. HCl No smell of ammonia Amide absent

Add more conc. HCl, cool to OdegC, add solid NaNO2,

betanaphthol in alkali maintaining temp. at 0degC Bright red dye Anilide

3)0.1g + 2ml conc. H2SO4. Shake, add K2Cr2O7 powder Bluish pink color Anilide

Nitrocompounds:

1)Reduction1g compound+0.5g Tin or Zn dust+ 5ml conc. HCl in china dish.

Boil, filter, Divide the filtrate to 2 parts

a) Filtrate+ CHCl3+ alc.KOH. Heat Foul smell of isocyanide

reduced soln. contains

primary amine

b)Filtrate at 0degC+cold soln. of NaNO2 and Betanaphthol in

alkali Bright red dye

original compound contains

nitro group

2) compound + 3-4ml alcohol+ 5-6drops 10% CaCl2 soln.+Zn dust.

Boil, filter. Filtrate + Ammonical AgNO3 (Tollen's reagent) Black ppt. or silver mirror Nitro compound

3)0.1g compound+ FAS (3-4ml of 5% Soln.)+ KOH in methanol til

appt. is obtained. Cork and shake

Green Fe(OH)2 is oxidized to brown

Fe(OH)3 by nitro group Nitro compound

4) Janowsky Reaction:

Substance + acetone+ xs 10% NaOH Faint yellow/no color Mononitro

Violet/Blue Dinitro

Red Trinitro

lab manual msc. chemistry

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