Qualitative Organic Analysis (organic chemistry-1 practical )

     

Qualitative organic analysis used for the identification  and characterization of unknown organic  compounds.
                  The systemic analysis used for the identification of a simple unknown organic compound contain the following steps:- 

•  Preliminary Observation
• Ignition Test
• Elemental Analysis
• Solubility Behavior
• functional Group Analysis
• Determination of Physical Constant
• Reference to literature and Naming the Compound
• Preparation of Suitable solid derivative and determining the melting point of crystallized derivative

1.Preliminary Observation:

S . No	Test	Observation	Inference
1	State	Solid	May be carboxylic acid , carbohydrate etc.
		Liquid	May be Alcohol, ether, ester, aldehyde ,Ketone, amine, phenol
2	Colour	Colorless solid	May be Carboxylic acid, amide, aniline, carbohydrate etc.
		Pink solid	May be resorcinol or napthol
		Yellow Solid	May be into Compounds
		Colorless liquid	May be ester, alcohol, ketone. aldehyde, hydrocarbons etc.
		Reddish brown liquid	Amines
3	Odour	Bitter Almond	May be Benzaldehyde or nitropuside
		carbolic or Phenolic	phenol
		Cinnamon like	Cinamic acid
		Fishy	amine
		Pleasant	Alcohol
		Fruity	ester
		kerosene	Hydrocarbon
		Very pungent	Halogenated derivative
		Naphthalene like	Naphthalene
		Odourless	May be carbohydrate, acid amide etc.

S . No	Test / Experiment	Observation	Inference
1	Bayer's Test : 0.1 gm. or 3-4 drops of organic compound + 1-2 ml of Na2CO3  +1-2 drops of KMnO4 & Shake	Decolourisation	Indicates aldehyde or unsaturated compounds
2	With Bromine water	No decolourisation of KMnO4	Indicates saturation Compounds

2. Ignition Test:-

S . No	Test / Experiment	Observation	Inference
1	Ignite a pinch of Organic compound on a nickel spatula	Burns with sooty flame	Aromatic
		Burns with non-sooty flame & residue is left without a sooty flame. Darkens, Swell, Chass with burnt sugar odour	Aliphatic Urea Carbohydrate

S . No	Test / Experiment	Observation	Inference
2	Beilstein Test :- Heat one end of a small copper wire to redness in a non-luminous paet of bunsen flame untill no green colour is impacted to the flame, cool and dip the wire in a small portion of  organic compound and  reheat in it in the non luminous paet of the bunsen flame	Green	Indicates halogen

Note : If the given organic compound sample is liquid, then of out its boiling point at this stage

3. Elemental Analysis:-

Prepare sodium Fusion Extract (S.F.E) & utilize it for the test following:-

S . No	Test / Experiment	Observation	Inference
1	Test for Nitrogen: 1ml S.F.E + 2-3 drops FeSO4 Boil the solution + add FeCl3& add diluuted H2SO4 * If a blood red colour is developed after the addition of FeSO4 Nitrogen & sulpur to be present together.	Prussion Blue	Indicates nitrogen
2	Test for Sulphur :- a) 2ml of S.F.E + 1ml soloution Nitroprusside solution	Pink colour	Presence of Sulphur
	b) 1ml of S.F.E +1ml acetic acid + few drops of Lead acetate and heat to boil	Black ppt	Presence of Sulphur
3	Test for Halogens:- 2ml S.F.E + 1ml dilute HNO₃ + excess of  AgNO3 solution Decant the another liquiour and treat the ppt with excess of NH₄OH	Precipitate froms	Presence of Halogen
		a) White ppt soluble in NH₄OH
		b) yellow ppt insoluble in NH₄OH
		c) pale yellow ppt springly soluble in NH₄OH
	Conduct the following test only if ppt is observed after the addition of Agno3 . 1ml S.F.E + excess of chlorine water + 2-3 drops of CCl4	Brown or Yellow globules pink globules

4 Solubility Behaviour :-

.

Group I	Group II	Group III	Group IV	Group V	Group VI	Group VII
Water & Ester sol uble	Water soluble Ether insoluble	solu ble in 5% HCl	Soul uble in 5% NaOH	soluble in cold conc H₂SO₄	Insolu ble in cold conc H₂SO₄	organic compou nds con taining N & ins oluble in HCl
Polyhy dric Phen ols	some amides	Ami nes	Acids	Aldehy des	Hydroc arbons	Amides
Reso rcinol	Urea, Thiourea	Ani line (1°) Tolu idin es (1°)	Benz oic acid Saly cylic acid	Benzal dehyde	Toluene Napthal ene	Benza mide
Ketones
Lower Aliphatic Acids, aldehy des, Alcohol etc.	Carbohy drate	Meth lani line (2°)	Cinna mic acid	Auto phe none Ben zop hen one	Diph enyl, Chlo robe nzene	Anilides Acetani lide
	Glucose	Ethyl anili ne(2°)	Phen ols	Alc ohol	Bromo ben zene	Benza nilide
		N,N- O met hyl anil ine (3°)	Phenol cresol α- Na pthol β- Na pthol	Benzyl alcohol esters Methyl salicyl ate Methyl benzo ate Ethyl Benzo ate	Benzyl choloride	Nitro compou nds Nitroben zene Di- nitroben zene Tri- nitroben zene

Note:- (i) If organic compound is insoluble in water, then there is no need of testing  its solubility in HCl

  (ii) If the Organic compound contain N-but insoluble in 5% HCl then directly go for Group -VII

5 Analysis of  Functional Groups:- 

Group-I (Polyhydric Phenols, Lower Carboxylic acids) 

S. No	Tests	Observations	Inference
1	0.1 gm of organic compound + Na2CO3	Effervescence No effervescence	Lower Carboxylic acid Phenol

* Conformatory test for Polyhydric Phenol

S. No	Tests	Observations	Inference
1	0.1 gm of organic compound+ 2ml of Water +1ml of Fecl3	Green, blue or violet colour	Confirms Phenol
2	Pathalein Test : 0.1 gm of organic compounds + 1-2 Crystals of Phthalic Anhydride +2 drops of conc H₂SO₄, heat gently for 1 minute, cool and add10% NaOH	Greenish yellow Fluoroscence	confirms resorcinol

Group- II (Some Amides, Carbohydrate)

Sl. No	Tests	Observations	Inference
1	0.1 gm of organic compound+ 10% NaOH, Boil expose the Vapours to red litmus.	Evolution of NH3	Amide
		Red litmus turns to blue	Urea
		No evolution of NH3 and red Litmus	Carbohydrate

* Thiourea :-

Sl. No	Tests	Observations	Inference
1	organic compound (100mg) +   naohf6 (2ml) heat for 1min cool, add 2drops of aq. lead acetate	Appearance of a dark brown or thiourea black colour due to the formation of sulphide	Thiourea
2	Organic compounds- Mest cool & dissolve the residue in h2o . Add fecl3 (Aq)	Blood red colour	Confirms Thiourea

* Conformatory Test for Urea:-

Sl. No	Tests	Observations	Inference
1	Biuret Test:- Heat the substance in a dry test tube until it melts , cool and dussolve the re-solidified organic compound in 1ml of dil NAOH add 1drop dil Cuso4	Pink, Violet, Blue	Confirms Urea
2	Urea-Nitrate Test :- Saturated solution of organic compound + conc. Hno3	crystalline white ppt	Confirms Urea

* Conformatory Test for Carbohydrate :-

Sl. No	Tests	Observations	Inference
1	Molish Test:- 0.1 gm of organic compound + 1ml of Molish reagent, add conc H₂SO₄ along the sides of  the tube	Reddish, Violet ring at the junction of two layer	Confirms Carbohydrate
2	Fehling Test :- 1 ml sample solution +1ml of Fehling reagent A+1ml of Fehling reagent B, heat on boiling water bath	Red  ppt	Confirms Urea
3	Benedicts Test:- 1ml of sample solution + 1ml of Benedicts reagents, heat on boling water bath	Red ppt	Reducing sugar
4	Tollen's Test :- 1ml of sample solution +1ml tollens reagent, heat on boiling water bath	silver mirror	Aldose
5	1ml sample sample solution +  pinch of solid lead acetate, heat to boiling, add 2drops of  NH3, once again heat to boiling	salmon pink	confirms glucose

Group III (Amines) :-

Sl. No	Tests	Observations	Inference
1	2-3 drops of organic compound  in dry test tube +few drops of acetyl or benzoyl chloride	A brisk reaction with evolution of heat after with separation of solid no brisk reaction and evolution of heat is absent	1° or 2° amine
2	Carbyl Amine test : 2-3 drops of organic compounds + 20drops of CHCl₃ + 1ml alcoholic KOH	A disagreeable smell of isocyanides	confirms 1° amine
3	Diazotisation :- 2-3 drops of organic + 3ml of conc HCl + 2ml of ice cold nano2	A transparent solution to this solution add ice cold b-napthol in NaOH
		a) An orange red dye is obtained	1° Amine
		b) A yellow oily emulsion	2° Amine
		c) A  red oil separates	3° Amine

Group -IV Acids,Phenols:-

Sl. No	Tests	Observations	Inference
1	0.1gmor 2-3 drops of organic compound+ NaHCO₃	Brisk effervescence No brisk effervescence	Phenol Indicates carboxylic acids or phenol
2	Litmus test : Sample +HCL + NaHCO₃ 80%	Blue to Red	Indicates carboxylic acid or phenols

Conformetry Test For Carboxylix Acids

Sl. No	Tests	Observations	Inference
1	Esterification test:- 0.1 gm of organic compound  + 0.5ml of methanol + 0.5ml of conc H₂SO₄ , heat, cool and pour in water	Fruity odour	Confirms   Carboxylic acids
2	0.1 gm of organic compound + Neutral  FeCl3	Violet colour	Confirms phenolic acids (salicylic acids)
3	a) 0.1 gm of organic compound +Br2 water	Decolourisation	confirms unsaturated
	b) 0.1 gm of organic compound + KMnO₄	Decolourisation No Decolourisation	carboxylic acids Cinnamic acids Benzoic acid

Conformatory Test For Phenol :

Sl. No	Tests	Observations	Inference
1	2-3 drops of Organic Compounds + Neutral Fecl3	Green, Blue or Violet	Confirms Phenol
2	Pathalein Test :- 2-3 drops of Organic compound + 2 crystals of Pathalic anhydride + 2-3 drops of conc H₂SO₄ Heat for 1 minute	Red	Phenols or Cresol

Group - V ( Aldehydes, Ketones, Alcohols, Esters) :-

Sl. No	Tests	Observations	Inference
1	2-3 drops of Organic Compounds + 2,4- dinitro phenyl hydrazine Boil &cool	Yellow or Red ppt Yellow ppt	Aldehyde or Ketone Aldehyde or ketone
	or organic compound + alcohol + phenyl hydrazine Heat on Water bath for 10 minutes	No ppt	Alcohol or ester

 

 Test For Aldehydes And Ketones:-

Sl. No	Tests	Observations	Inference
1	2-3 drops of Organic Compounds + Schiff's reagent	Pink colour immediate is restored in the aquous layerNo pink colour	Aldehyde Ketone
2	Organic Compounds +Tollens reagent, heat on boiling water bath	Bright silver mirror	Aldehyde
3	Fehling Test :- Organic compound + 1ml of Fehlings reagent A + 1ml of Fehlings reagent B Heat on boiling water bath ( pest for aldehyde )	Red PPt	Aldehyde
4	Organic Compound + Sodium nitropuside + NaOH	Red	Ketone with Ch3C group
5	Iodofrom Test :- Organic Compound + Iodine solution + excess Naoh warm	Yellow ppt	Methyl Ketone
6	Organic Compound + Napthalene, heat and add dry sodium	Green or blue of Na piece	Keto like Benzo phenon

Test For Alcohols :-

.

Sl. No	Tests	Observations	Inference
1	Sodium metal test :- Take organic compound in a dry test tube + add a piece of sodium metal	Brisk evolution	Alcohol
2	0.5 ml of organic compound + 0.5 gm of benzoic acid + 0.5 ml of conc H₂SO₄ boil for two minutes cool and pour in water	Fruity odour	Confirms Alcohols

Test For Esters :- 

Sl. No	Tests	Observations	Inference
1	Hydroxamine Acid  test :- 2-3 drops of Organic Compound + 5ml of hydroxylamine hydrochloride solution in methyl alcohol + 0.5 ml of 10% solution of KOH, Boil, cool and add 1drop of FeCl3	Purple or wine red colour	Confirms ester
2	2-3 drops of organic compound + 2drop of phenolphthalein + few drops of dil NaOH, boil	Pink colour discharge	Confirms ester

Group - VI (Hydrocarbons) :-

Sl. No	Tests	Observations	Inference
1	sample + conc h2so4 + solid k2cr2o7 shake well	Green colour	Hydrocarbon
2	2-3 drops of organic compound + Conc H2so4, boil for 5 minutes and pour in water	A clear solution is Obtained Without separation of oil	Hydrocarbon
3	2-3 drops of Organic compound + 0.5 ml of dimethyl sulphate, heat to boiling	A clear solution is obtained	Hydrocarbon

Group -VII(Amides, Anilides, Nitro compound)  :-

   Test for Amides :-

Sl. No	Tests	Observations	Inference
1	0.1 gm of organic compound + 5ml of dil NaOH Boil and expose a wet red litmus paper to the gas	Red litmus turns to blue	Amide
2	Cool the above solution and add conc HCL	White solid separates out	Amide

  Test for Anilids :-

Sl. No	Tests	Observations	Inference
1	Tafels Test organic compound +5ml conc H₂SO₄, shake well. Add pinch of K2Cr2O7	Red or violet colour changes to Green	Anilide present
2	0.1 gm of Organic compound + KOH solution +chcl3 and boil	Disagreeable smell of Carbylamine	confirms Anilide
3	0.1gm of organic compound + 2ml of conc HCl ,boil , cool and add 2ml ice cold Nano2 solution and then ice cold  β-naphthol in NaOH	Bright  orange red dye	confirms Anilide

    Test For Nitrohyodrocarbon :- 

Sl. No	Tests	Observations	Inference
1	0.1 gm of Organic compound + few pieces of zinc or tin + 3ml of conc HCL, boil, filtter, cool the filterate and add ice-cold solution of Nano2 and in naoh	Red dye	Nitro compound
2	Mulliken's Reaction :- O.1 gm of organic compund + 2ml of alcohol + 10% solution of cacl2 , boil, filtter & add Tollen's reagent to the filterate	Ash grey ppt	Nitro Compound

Conduct the following test only if halogens are present in organic compound

Sl. No	Tests	Observations	Inference
1	2-3 drops of organic compound + Alcoholic AgNo3 and warm,	1. White ppt 2. No ppt even on Warming	1.Nitro compound Halogens is the side chain 2. Nuclear Halogens

3. Ianowsky Reaction

Sl. No	Tests	Observations	Inference
1	0.1 gm. of organic compound + 5ml of Acetone, 2ml of NaOH, Shake well+ sodium nitropuside	1. Red colours 2. Pink or Violet colour	1.Nitro compound Halogens is the side chain 2. Nuclear Halogens
2	Organic compound +5ml acetone+ NaOH + Glacial acetic acid	Turns red	Trinitro compound

If the given organic compound is solid then find out its melting point after functional group analysis