HEMICAL TEST TO DISTIN: LEVELA TEST. REAGENT INFERENCE, 1: lodoform test(Alcohols) Z-Lucas test (1°,2",& ZnCl,/HCl Turbdity immediately in 3°Alcohals 3°Alcohols) +3-Neutral ferric chloride test ‘Neutral FeCls Voilet colour (Phenol) 4-Bromine water test{Phenol) | 8r./H;0 White ppt ‘S-lodoform NaOH/Ip Yellow Ppt of CHI, test(Aldehydes&Ketones: -COCH; Alcohol(-C(OH)CH, 6-Toliens test(Aliphatic & “Amm.AgNOs Silver mirror at walls of test tube Aromatic Aldehydes) 7-Fehting test(Aliphatic Aldehydes) Fehling A & Fehling B Reddish Brown ppt af Cu;0 8-Azo dye test(Aniline) ‘ailing forms BDC with NaNO,+ HCI than reacts with /3 - nathal S-tsocyanide test(1° Aniline) CHCl, + KOH Unpleasent odur or smell of Isocyanide CsHs80,C1 Product of 1° Amines soluble in alkall, 10-Heinsberg test(1” 2 3° Amines) Product of 2° Amines are insoluble in alkali, 11-Sodium bicarbonate test (Acids) | NaHCO, Effervesence due to CO; 12. aq.NaOH and AgNO, test Test Ppt formed if-Ci/-X directly attached tosp* : 5 : a : al jes (R- RCHO + 2 [Ag(NH,)2I° + 30H RCOO' + 2Ag Tollens’ Reagent Note: HCOOH(methanoic acid ) also gives this test, ketones(RCOR} do not give thi LEVELB silver +2 RCOR + 2,4-DNP > Orange ppt R-CHO + 2,4-DNP > Orange ppt Aldehydes and ketones having CH,CO- (keto methyl) group give lodoform Test, Alcohols having CH;CH- group also giv lodoform Test. +4NHs silver ppt testCH;CHO +31, +4.NaQH > CHI, + HCOONa +3 Nal +3H,0 Yellow ppt The following compounds give lodoform Test: ethanol (CHsOH), propan-2-ol (CH,CH(OH)CH;), ethanal(CH;CHO), propanone(CH;COCH,), butanone ( CH;COCH,CH;) , pentan-2-one (CH;COCH, CH,CH,) , acetophenone ( PhCOCH; ) 4. All carboxylic acids ( R-COOH} give Bicarbonate Test RCOOH + NaHCO, RCOONa + CO, + H,0% effervescence 5. Phenol gives FeC); Test GHsOH + FeCl> (CH0),Fe + 3 HCI (neutral) (violet color) 6. All primary amines (R/Ar -NH,) give Carbyl Amine Test R-NH, + CHCl, + KOH(alc) > R-NC + KCI + H,0 offensive smell 7. Aniline gives Azo Dye Test ( Only for aromatic amines! CoHsNHz +NaNOz+HCI > CeHsN2°CI'; then add B-naphthol > orange dye 8. All alcohols (ROH) give Na-metal test ROH + Na > R-ONa + H, bubbles 9. For esters (RCOOR) : Hydrolyses first. Then see the products ( acid & alcohol) and give a test to identify them 10. All alkenes (C=C) and alkynes (C=C) decolorizes Br, — water from red to colorless 11, Lucas Test to distinguish primary, secondary and tertiary alcohols Lucas reagent: ZnCl,/HCl 3*-alcohol + Lucas reagent -> immediate turbidity 2°-alcohol + Lucas reagent > turbidity after sometime 1°-alcohol + Lucas reagent -> no turbidity CBSE QUESTIONS Give one chemical test to distinguish between the following pairs of compounds: 1, Methylamine and dimethylamine 12. Ethanal and Propanal 2, Secondary and tertiary amines 13. Acetone and Acetaldehyde 3. Ethylamine and aniline 14. Acetaidehyde and Benzaldehyde 4. Aniline and benzylamine 15. Ethanoic acid and Ethnoyl chloride S. Aniline and N-methylaniline 16. Methanol and Ethanol 6. Propanal and Propanone 17. Propanol and Propan-2-ol 7. Acetophenone and Benzophenone 18. 2:Methy! Propan-2-ol and Propanol 8. Phenol and Benzoic acid 19. Phenol and Cyclohexanol 9. Benzoic acid and Ethyl benzoate 20. 1°,2°,83° Alchols 10, Pentan-2-one and Pentan-3-one 21. 1°.2°,& 3° Amines 11. Benzaldehyde and Acetophenone 22. Formic acid and Acetic acid11.15 DISTINCTION TEST BETWEEN PHENOL an AND ALCOHOL Dove, / ./ Ferric chloride test; Phenol gives violet colour with FeCl, but alcohols do not. 3C,H,OH + FeCl; —> (C,H,0);Fe** +3HCl Phenol Ferric phenoxide (Violet) C,H,OH + FeCl; —— No effect 2. Ceric ammonium nitrate test © Ceric ammonium nitrate (CAN) gives red colour with alcohols but there is no response with phenol. 2ROH + (NH4)2Ce(NO3)¢ —> [(ROH),Ce(NO;)4] Alcohol CAN Red coloured complex +2NH,NO, 3. Bromine water test : On shaking phenol with Bry water we get white precipitate of 2,4,6-tribromophenol while alcohols do not give this test.11.16 DISTINCTION OF PRIMARY, SECONDARY AND TERTIARY ALCOHOL f /. . }OVictor mayer test This test involves following ~ (i) Alcohol is reacted with conc. HI or red phosphorus and iodine to form the corresponding alkyl iodide. (ii) Alkyl iodide is treated with silver nitrite when corresponding nitro alkane is formed. (iii) Nitro alkane is treated with nitrous acid (NaNO, + H,SO,) and the solution is made alkaline by addition of excess of caustic soda. If blood red colouration appears, it indicates a primary alcohol. If blue colouration appears, it indicates a secondary alcohol. If the solution remains colourless, it indicates a tertiary alcohol. Primary Secondary feriiars R R R —CH,OH cou >c—on R R P/I,|or HI P/I, jor HI P/I lor HI f R R R—CHI >cu R>CH1 R R AgNO, AgNO, AgNO, R R R—CH,NO, CHNO, R>C—NO, R R HONO, HONO HONO, R R—E—NO2 >on: No reaction R NOH NO [neon Nitrolic acid Pseudo nitrol C olourtess NaOH NaOH Blood red colour Blue coloura was test This test is based upon the difference in éactivity of primary (1°), secondary (2°) and tertiary (3°) alcohols with conc. HCl. Alcohols react with an equimolar mixture of concentrated hydrochloric acid and anhydrous zinc chloride at room temperature to form alkyl halides, ZnCl R—OH + HCl ——2, pR_, Alkylaleohol (conc.) Anhyd. iy, ainda 2? The three types of alcohols undergo this reaction at different rates. The rates of reaction with Lucas reagent [cone. HCI+ ZnCl, (anhydrous)} follow the following order: tertiary Alcohol > secondary Alcohol > Primary Alcohol R—CH,OH+ He] —28C2_, No reaction primary Alcohol (conc.) Anhyd. and hence no turbidity at room temperature ZnCl R,CH—OH+ HCl ——25 R,CH—Cl +H,0 secondary (cone.) Anhyd. Turbidity appears Alcohol in about 5 minutes ZnCl R,c—on+ Ho] “2, Rca +H,0 tertiary (cone.) Anhyd. Turbidity appears Alcohol immediately The alkyl chloride formed is insoluble in the medium, thus the solution becomes cloudy before it separates as a distinct layer. The following observations are made: (a) If cloudiness (white turbidity) appears immediately, the alcohol is tertiary. (b) Ifcloudiness appears in about 5 minutes, the alcohol is secondary. (c) If the solution remains clear, i.e., no cloudiness is formed, the alcohol is primary.Example 7__How will you distinguish between methyl alcohol and ethyl alcohol? Ethyl alcohol Tests Methyl alcohol |. Todoform test On heating with I, and NaOH Oil of wintergreen test On heating with salicylic acid and cone. H;SO, Ester test (On heating with glacial acetic acid and cone, H,SO, INo yellow compound is formed. |Gives characteristic odour of oil of wintergreen, ‘Yellow compound (CHI,) with characteristic lodour is formed, Does not give odour of oil of wintergreen, |Forms ethyl acetate which has a fruity odour. Forms methyl acetate with characteristic odour LTest [physical state 2, Odour 3, Solubility 4, Action of sodium 5. Action of water (hot) 6. Action of PCl, 7. Action of CH,COCI 8. Action of air 9. Oxidation Ethyl alcohol point 351.3 K. It is associated liquid due hydrogen bonding. Sweet, unconsciousness. Miscible with water. Hydrogen is evolved. No action. acetic acid. Volatile liquid, boiling alcoholic vapours do not bring Forms acetaldehyde and ener Volatile liquid, boiling point 307.5 K. No hydrogen bonding is present. an to Pleasant, ethereal vapours bring unconsciousness. Immiscible with water. No reaction. Hydrolysed to ethyl alcohol. Ethyl chloride is|No action in cold. formed. When heated with PCI, it forms ethyl chloride. Forms ethyl acetate|No action in cold. On (Sweet fruity smelling|heating forms a mixture liquid). of ethyl acetate and ethyl chloride. No action. Forms peroxide. Not easily oxidised. It can also form acetaldehyde and acetic acid with — strong oxidising agents.10. Action of strong|Ethyl salts are formed. |Oxonium salts are acids formed. Il. Action of HI Forms ethyl iodide in}Forms ethyl] iodide and ethyl alcohol in cold. On heating forms only cold.12.9 TESTS OF ALDEHYDE: Fermi ‘S AND KETONES (Distinction) Tests ns Aldebydes Ketones 1, With Schiff’ reagent (Give pla cob Woe 2. With Fehling’s solution Give red precipitate. [No precipitate is formed. 3. With Tollens reagent Black precipitate ofsilverorsilvermimroris formed. | No black previpiate o silver miror s fret 4, With saturated sodium bisulphite | Crystalline compound (colourless) is formed. Crystalline compound (colourless) is formed. solution in water 5. With 2: 4-dinitrophenyl hydrazine | Orange-yellow or red well defined erystals with | Orange-yellow or red well defined ervsls wit (Brady's reagent, DNP) melting points charecterstic of individual | meling points characteste of inital Astoes aldchydes. 6. With sodium hydroxide Give brown resinous mas (Formaldehyde does not | No reaction give this est) aldehyde doesnot respond | Red colour which changes to arse 17. With sodium nitroprusside and few | A deep red colour (Formaldehyde does no reso drops of sodium hydroxide to this test).eneral tests for carboxylic group (i) The aqueous solution of the acid tums blue litmus red. (i) The aqueous solution of the acid gives brisk effervescence of carbon dioxide with sodium bicarbonate or sot carbonate (sodium bicarbonate test). (iii) On heating with alcohol and concentrated sulphuric acid, a fruity smell of ester is formed, {iv) Acetic acid gives blood red or wine red colour on treatment with FeCl; due to the formation of ferric acetare 3CH,COOH + FeCl, —> (CH,COO); Fe +3HCI (v) Benzoie acid gives buff colour on treatment with neutral ferric chloride. 3CjH,COOH + FeCl; —> (CeH,COO), Fe +3HCI Benzoie acid Ferrie beraoate (buff colour) (oi) Neutral solution of formic acid gives red precipitate with Fehling’s solution, black precipitate (Silver miro) wih Tollens’ reagent and with mercuric chloride, it gives white precipitate which changes to grey black‘Amino cyclohexene 13.11 ANALYTICAL TESTS insberg’s Test : Lu insber t for distinction of 1%, 2 and 3°, chloride, ic., Hinsberg’s reagent (C6H,80. aoe I nes. tis very good test E ‘amines. The amine is treated with benzene sulphony! 2C1 and the resulting reaction mixture treated with excess NaOH or KOM. ‘esidue with benzene sulphonyl chloride which discolves re ‘excess NaOH of KOH _ H RNC “+! CV'SO.C Hy | ()Wamine: These amines form white “Cap PN TS0.C Hs MONG, te N_s0,0,H, Na H Benzene CHCD ” Neatiyibetes ° i,oy — neo Alkylamine—_sulphonyl Shovide ee (1° Amine) (tite residue) 2 amine : These amines also form white residue on treatment with benzene sulphonyl chloride but the residue is insoluble in aqueous NaOH or KOH. R \ Be N—H_+ C1 S0.CH, ——> SN—s0, C,H ? 2CoHs 2CeHs R ~ CHE p/ Dialkylamine NWN -itkytbenzene (2° Amine) sulphonamide (white residve) (insoluble in aqueous ‘NaOH or KOH) amine : These amines do not react with benzene sulphony! chloride hence no residue is obtained, Ss > C1SO,C,H; —> No reaction ae ee ae 5° Amine2 Carbytamine test: It is used to test primary amines. When these amines are heated with chloroform ant a « we get foul odour of 1socyamde, C HANH, +CHCI, +3KOH 25 CH NSC + 3KCL+ MLO Ethylamine acy thy iwoeyanide (unpleasemt st) 3. Aredye test : Aniline is first diazotised (with NaNO, + HCI at 273-278 K) to form benzenediazonium chionae 9 adding alkalme solution of -naphthol to the diazotised product, an orange red dye is formed © NH; +HONO + HEL 223278, © NeeNCL + 21,0 OH sNmNCT pH 10 ae 1-Phensaso-2-maphthot torange dyer43.12. DISTINCTION BETWEEN PRIMARY, SECONDARY AND TERTIARY AMINES Tertiary amine 7. Jaction of CHCl, and alcoholic|Bad smelling _carbylamine|No action, No action. [KOH. (Carbylamine test) |(Isoeyanide) i formed. 2, |Action of CS,and HgCl, Alkyl isothiocyanate is formed) No action. INo action. (Mustard oil test) which has pungent smell like mustard oil 4. | Action of nitrous acid Alcohol is formed with evolution of|Forms nitrosoamine which gives|Forms nitrite in cold wh nitrogen. green colour with phenol and cone. heating gives nitrosoamine » H,SO, (Liebermann’s test. responds to Liebermann’s tet 4, [Action of acetyl chloride. [Acetyl derivative is formed. Acetyl derivative is formed No action. ', |Action of Hinsberg’s reagent. |Monoalkyl sulphonamide is formed|Dialky! sulphonamide is formed|No action. which is soluble in KOH. ‘which is insoluble in KOH. 6, |Action of methyl iodide. 3 molecules (moles) of CHsIto form|2 moles of CHI to form quaternary |One mole of CH ylto form guste) Jquaterary salt with one mole of]salt with one mole of secondary) salt withone mole of tertiary ame primary ami lemine.13.25 DISTINCTION BETWEEN ETHYL CYANIDE AND ETHYL ISOCYANIDE cee Test Ethybevanide, | Fthyl isocyanide, CMON | CHC de tenn ce nandeescaline sf ac Sate aoe i 1.) Odour Not unpleasant | Extremely unpleasant 2. Solubibty in water |Soluble Insoluble | 3. Hydrolysis by acid | Yields propionic acid | Produces ethy lamine ICH.CN —> C;H.NC — C,H .COOH CSH.NH, 4. Hydrolysis by alkali | Same as in test 3 No action Gives — propylamine | Gives |(Primary amine) ethy methylamine (Secondary amine) wn Reduction No effect 6. Heating at S20 K |Nitroethane s Vest Exayt nite (CHONDy Nitrocthune (C,H.NO:) i ea (AlkSI nitrite, RON) (Nitrwathane, BNO) Low. 290K 2. Reduction with metal and | Give alcohot ~ hydroxyl amine or NH ‘Gives corresponding primary amine aed (SnHCH or with | CSH,ONO ~ 4H —s CHOH- NHLOH | CH.NO. > 6H —> CH.NH, ~ 21,0 Lilt, RONO + 6H ROH NH LO | R=NO.» GH RNH, 210 ‘Much higher. 388K. 2 AnmnctMeoHtataien, | Ketily. béabned tg coapn | Nt pope ef rw pean, ty Alcohol and sodium nite dscomponten) | frm sche sodium sal, beau pom of alka te CHLONO” NaOH "+ GH.ON- NoNO. i fom changes mao, wih dslves alka R--ONO- NAOH = RON” NaNO, wlermsodume ox eH eH cH mimennd 4. Action of HINO No action with nitrous acid Primary nitroalkanes forms ai (NaNO. HCH alkali to give red solution | R—CiH, - O- NOH —> R—C on ie acid, which dissolve sn OH } Noy No. | Secondary nitroalkanes yields pseudo-nitrol. which dissolves | | imatkalito give blue solution {Hz HONO —> R,—C—NO