SOME USEFUL TIPS FOR SOLVING ORGANIC PROBLEMS

S. No	Experiment / Properties	Observation	Inference
1	Smell / Odour	a) Pleasant	May be Esters, Ethers Ketones  or Nitro alkanes
		b) Bitter almonds	Benzaldhyde, C6H5 –CHO Nitro benzene, C6H5 –NO2
		c) Carbolic acid	Phenols
		d) Fishy	Amines
		e) Jasmine	Benzyl acetate, C6H5 CH2COOCH3
		f) Foul / Offensive	Acroleine, CH2 = CH – CHO or Alkyl isocyanide, R –N ≡ C or Aryl isocyanide, Ar –N ≡ C
		g) Pungent mustard like	Alkyl isothiocyanate, R –N = C = S
2	With metallic Sodium	a) H2 gas evolved	Alcohol (– OH group) is present
		b) No reaction	May be ether (– O – group)
3	With NaHCO3 or Na2CO3 solution	Brisk effervescence of CO2	Carboxylic acid (– COOH group) is present
4	Victor Meyer’s Test	a) Red colour	1o alcohol (– CH2–OH group) is present
		b) Blue colour	2o alcohol (> CH–OH group) is present
		c) Colourless	3o alcohol (> C–OH group) is present           |
5	With Conc. HCl and anhydrous ZnCl2 (Lucas Test)	a) Immediate turbidity or cloudiness	3o alcohol (> C–OH group) is present            |
		b) Turbidity or cloudiness after 5-10 minutes	2o alcohol ( > CH–OH group) is present
6	With Carboxylic acid and Conc.H2SO4 (Esterification)	Pleasant smelling ester is formed	Alcohols (– OH) present
7	With neutral FeCl3	Violet colour	Phenol, C6H5 – OH
8	a) With neutral FeCl3	Violet colour	Salicylic acid, o- HO– C6H4 – COOH
	b) With NaHCO3 or Na2CO3 solution	Brisk effervescence of CO2
9	With Bromine water (Br2 / H2O)	a) White precipitate	Phenol, C6H5 – OH
		b) Yellow precipitate	Aniline, C6H5 – NH2
		c) Decolourises	Unsaturated compund (–C = C– , –C ≡ C–)
10	With Tollen’s reagent (Ammoniacal AgNO3)	Silver mirror is formed	Aldehydes (– CHO), Formic acid (HCOOH), Glucose, Fructose or Tartaric acid
11	With Fehling’s solution	Blue colour becomes Red colour	Aliphatic Aldehydes (– C – H)      | |      O
12	With Schiff’s reagent	Red / Pink colour is restored	Aldehydes, – CHO
13	With I2 and NaOH (Haloform reaction)	Iodoform is formed	Ketones (CH3 – C –),                           | |                           O Ethyl alcohol, Isopropyl alcohol,    (CH3– CH –),             |            OH
14	When oxidised	Gives acid	May be aldehyde or ketone  (– C – )       | |       O
15	When strongly oxidised by K2 Cr2 O7 or KMnO4	Gives acid	May be alcohol (– OH)
16	When reduced by reducing agents such as Li Al H4 or Na/Hg in H2O	a) Gives 1o alcohol (– CH2 – OH)	Aldehyde (– CHO)
		b) Gives 2o alcohol (> CH – OH)	Ketone (– C –)                  | |                  O
17	Dry distillation of Calcium salt	a) Gives Acetone	Acetic acid, CH3 COOH
		b) Gives Benzophenone	Benzoic acid, C6H5 COOH
		c) Gives Formaldehyde	Formic acid, HCOOH
18	Heated with Soda lime (NaOH + CaO) (Decarboxylation)	Benzene is got	Benzoic acid, C6H5 COOH
19	With nitrous acid (NaNO2 + HCl)	a) Alcohol is formed with the liberation of N2	1o amine (– NH2 group) is present
20	With CHCl3 and alcoholic KOH or NaOH (Carbylamine reaction)	b) Oily nitroso amine	2o amine (> NH group) is present
		Foul smelling isocyanide is given out	Primary amine (– NH2 group) is present
21	With CS2 and HgCl2  (Mustard oil reaction)	Pungent mustard like odour	Primary amine (– NH2 group) is present
2	With metallic Sodium	a) H2 gas evolved	Alcohol (– OH group) is present
22	Optically active compounds	----	CH3CH(OH)CN, 2–Butanol, Lactic acid, Tartaric acid, Glucose, Fructose, α - Aminoacids (Except – Glycine)
23	Exposure to air or light	a) Liquid or Crystalline Solid turns Pink or Red	Phenols
		b) Liquid turns Brown	Aniline, C6H5 –NH2
		c) Crystalline Solid turns Brown	Benzene diazonium chloride, C6H5N2Cl

 * The above tips are useful:-

 # for solving organic problems easily;

# # to answer the questions like  -  
Distinguish one compound from the other, Test for compounds, etc,.

TIPS TO IDENTIFY ORGANIC COMPOUNDS