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w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om COO – 1 ORGANIC COMPOUND CONTAINING OXYGEN Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 2 C O N C E P T S (Monohydric Alcohols & Ether) Alcohols : C1A Physical Properties : The lower alcohols are completely soluble in water but as the number of carbon atoms increases, solubility decreases. This solubility in water is due to intermolecular H-bonding between water and alcohols molecules due to their polar character. Increase in C-chain increases organic part hence solubility in water decreases. Isomeric 10, 20, 30 alcohols have solubility in order : 10 > 20 > 30. C1B Method of preparation of Alcohols : Hydration of Alkenes : w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om (i) dil H SO 2 4 Intermediate is carbonium ion that can change to more stable carbanion ion by hydride shift, alkyl or phenyl shift. (ii) Hydrolysis of Alkyl Halides : R – X + aq. NaOH (or H2O) R – OH + NaX (or HX) Reaction can be S N1 or S N 2 . (iii) Reduction of Carbonyl Compounds (including acid derivative) : RCHO 4 4 RCH 2 OH 10 (b) 4 4 (c) (iv) LiAlH or NaBH (a) LiAlH or NaBH Acid, acid halide, ester and anhydride are reduced to 10 alcohol. Hydroboration and oxidation : H O , OH BH in THF 2 CH 3 CH CH 2 3 (CH 3 CH 2 CH 2 ) 3 B 2 CH 3 CH 2 CH 2 OH B(OH ) 3 The hydroboronation-oxidation (HBO) process gives product corresponding to anti-Markownikoff addition of H2O to the carbon-carbon double bond. (v) Oxymercuration-Demercuration : Hg ( OAc ) 2 H 2O NaBH 4 The alcohol obtained corresponds to Markownikov’s addition of water to an Alkene. (vi) (a) Through Grignard Reagent : Addition of Grignard Reagent on carbonyl compounds followed by hydrolysis yields alcohols nature of which depends upon types of carbonyl compounds used. Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 3 H O 3 + H2O R1, R2 can be H, alkyl or aryl but R3 is not H. Grignard reagent with epoxide and after hydrolysis gives 10 alcohol for e.g., (b) H O 2 Practice Problems : 1. Propene, CH3 – CH = CH2 can be converted into 1-propanol, Which of the reagent among the following is ideal to affect the conversion : alkaline KMnO4 (b) B2H6 and alkaline H2O2 w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om (a) (c) O3/Zn (d) OsO4/CH2Cl2 (b) 2. Glycol may be obtained : (a) by the oxidation of ethylene with cold, dilute, alkaline permanganate solution (b) by the hydrolysis of ethylene bromide under reflux with aqueous sodium carbonate solution (c) by the hydrolysis of ethylene chlorohydrin on boiling with aqueous sodium bicarbonate (d) by any of the above methods (d) 3. Which of the following are the starting materials for the Grignard’s synthesis of tert. butyl alcohol (a) CH3MgI + CH3COCH3 (b) CH3MgI + CH3CHOHCH3 (c) CH3CH2MgBr + CH3COCH3 (d) CH3CH2MgBr + CH3CHO (a) [Answers : (1) b (2) d (3) a] C2 Chemical Properties : (i) Dehydration of Alcohol : conc . H SO 2 4 Alcohols leading to conjugated alkenes are more easily dehydrated then those of alcohols leading to non-conjugated alkenes. Dehydration of alcohol is in the order 30 > 20 > 10 as intermediate is carbocation. (ii) Reaction with Halogen Acids : R – OH + HX RX + H2O Intermediate is carbonium ion. The order of reactivity of HX : HI > HBr > HCl for a given alcohol. (iii) Reaction with Phosphorous Halides and Thionyl Chloride : 3R – OH + PX3 3RX + H3PO3 (X = Br, I) R – OH + SOCl2 RCl + SO2 + HCl (iv) Acidic Character of Alcohol : RO – H + Na RO–Na+ + ½ H2 Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 4 alkoxide The order of acidic character of alcohol with metal is : CH3OH > 10 > 20 > 30. The relative acidities is as follows : RCOOH > C6H5OH > H2O > ROH > CH CH > NH3 > RH (v) Ester Formation (alcohol can act as a nucleophile also). Thus reactivity of alcohols for given acid is in order : CH3OH > 10 > 20 > 30 w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om and those of acids for given alcohol is in order : HCOOH > CH3COOH > RCH2COOH > R2CHCOOH > R3CCOOH (vi) Oxidation of Alcohol : 1. Using Cu Cu (a) CH 3 CH 2 OH CH 3CHO H 2 0 300 C 0 1 Aldehyde Cu 0 (b) 300 C Cu 0 (c) 300 C 2. Oxidation using KMnO4/K2Cr2O7 (a) ( i ) KMnO RCH 2OH 4 RCOOH ( ii ) H (b) KMnO , CrO in glacial acetic , acid or K Cr O (c) 3. C3 4 3 2 2 7 Other reagents used for oxidation : (a) PCC (pyridinium chlorochromate) to oxidise 10 alcohols to aldehydes. (b) MnO2 selectively oxidises the OH group of allylic and benylic 10 and 20 alcohols to give aldehydes and ketones respectively. Test to distinguish 10, 20 and 30 Acohols : (a) Lucas Reagent (anhydrous ZnCl2/conc. HCl) (b) Oxidation (c) Victor Meyer Test Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 5 Practice Problems : 1. Identify (Z) in the following reactions series : PBr Alc . KOH H SO , room temp . Ethanol 3 ( X ) ( Y ) 2 4 ( Z ) H 2 O , heat (a) 2. (b) CH3CH2OH (c) CH3CH2OSO3H (d) C2H5OC2H5 An organic compound gives hydrogen on reacting with sodium metal. It also gives iodoform test and forms an aldehyde of molecular formula C2H4O on oxidation with acidified dichromate. The compound is : (a) CH3OH (b) CH3COOH (c) CH3CHO (d) C2H5OH The order of reactivity of the following alcohols, w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om 3. CH2 = CH2 towards conc. HCl is (a) I > II > III > IV (b) I > III > II > IV (c) IV > III > II > I (d) IV > III > I > II [Answers : (1) b (2) d (3) c] C4 Ethers Nomenclature of Ethers : Cyclic ethers can be named in severay ways : In another system, a cyclic three membered ether is named as oxirane and a four membered ether is called oxetane. C5 Methods of Preparation of Ether : (a) Williamson Synthesis : Example : (i) Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 6 (ii) Discussion : Phenol in Williomson’s synthesis : Because phenols are stronger acids than alcohols they can react with NaOH to change into sodium phenoxide ion. But alcohols can be converted into sodium alkoxide ion by reaction with sodium metal only. [Alkyl halide used here can not be aryl halide as it does not undergo nucleophilic substitution easily] R – X can be X = –Cl, –Br, I, (b) – OSO3CH3 etc. Ethers by Intermolecular Dehydration of Alcohols : Alcohols can dehydrate to form alkenes. w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om 10 Alcohols can also dehydrate to form ethers. The formation of ether takes places by S N 2 mechanism mainly, with one molecule acting as the nucleophile and with another protonated molecules of the alcohol acting as the substrate. Finally this method is not useful for the preparation of ether with 30 alcohol because they form alkene too easily. This method is not useful for the praparation of unsymmetrical ethers from primary alcohols because the reaction leads to a mixture of products. (c) Ethers may be prepared by the addition of alcohols to alkenes in the presence of acid e.g. Practice Problems : 1. Which route provides a better synthesis of ether : (a) I (b) II (c) equal (d) none [Answers : (1) b] C6 Reactions of Ethers : (a) Ethers are comparitavely unreactive compounds. The ether linkage are quite stable towards bases, oxidizing agent, reducing agents. Ether can undergo just one kind of reaction, cleavage by acids : HX R O R HX RX R OH RX R X Reactivity of HX : HI > HBr > HCl Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 7 Cleavage takes place only under quite vigourous conditions : concentrated acids (usually HI or HBr) and high temperature. Oxygen of the ether is basic, like the oxygen of alcohol. The initial reaction between an ether and an acid is undoubtedly formation of the protonated ether. Cleavage then involves the nucleophilic attack by halide ion on this protonated ether, with displacement of the weakly basic alcohol molecule. w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om As we might expect primary alkyl group tend to undergo S N 2 and 30 tend to undergo S N1 . (b) Acid Hydrolysis : C 2 H 5 O C 2 H 5 H 3O 2C 2 H 5OH . (c) Acid Hydrolysis of Epoxide : (d) Formation of Halohydrin : H O 3 HX Practice Problems : 1. Ethoxy ethane does not react with (a) 2. HI (b) conc. H2SO4 (c) PCl5 (d) Na An ether, (A) having molecular formula, C6H14O, when treated with excess of HI produced two alkyl iodides which on hydrolysis yield compounds (B) and (C). Oxidation of (B) gives an acid (D), whereas oxidation of (C) results in the formation of a mixed ketone, (E). Thus structures of (A) is (a) (b) (c) (d) CH3CH2CH2CH2OCH2CH3 [Answers : (1) d (2) c] Aldehydes & Ketones C7A Physical Properties : It has high dipole moment Boiling point are lower than alcohols due to their inability to form intermolecular H-bonding. B.Pt. are higher than corresponding alkanes due to dipole-dipole interaction. Carbonyl group can form H-bond with H2O hence they are soluble in water to varying extent. Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 8 C7B Method of Preparation : 1. Oxidation : (a) w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om (b) (c) This oxidation is called as oppenauer oxidation. 2. Rossenmund Reduction : 3. [LiAlH (O-t-C4H9)3 or Lithium tri-t-butoxy Aluminium hydride] 4. 5. Hydrolysis of Gem-Dihalide (a) (b) (c) 6. Cl , heat H O 2 ArCH 3 2 ArCHCl 2 ArCHO Hydration of Alkynes : Hydration of alkynes gives ketones (except CH CH which gives CH3CHO) (a) H O, H CH CH 2 CH 3 CHO (b) HgSO 4 Einstein Classes, H O, H CH 3 C CH 2 CH 3 COCH 3 HgSO 4 Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 9 7. Hydroboration Oxidation : Hydroboration of a non-terminal alkyne followed by oxidation of the intermediate yields a ketone but terminal alkyne yield aldehyde. 8. Use of Grignard Reagent : (b) 9. With HCN aldehyde is formed. w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om (a) With RCN a ketone is formed. With Esters (a) (b) 10. Decarboxylation of calcium salts of carboxylic acids : 11. Oxo Process : 2 CH3CH = CH2 + CO + H2 CH3CH2CH2CHO + [COH(CO)4] Cobal + Carbonyl hydride 12. Reduction of acid chloride with organocopper compounds : Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 10 13. Friedel-Crafts Acylation : (a) (b) 14. From Cadmium and Lithium Salts : 1. 2RMgX + CdCl2 R – Cd – R + MgCl2 + MgX2 w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om RCOR’ + RCdCl R – Cd – R + R’COCl R should be 10 alkyl or aryl (–C6H5) 15. Aldehyde/Ketone Ozonylysis of Alkene (Zn/H+) C8 Chemical Properties : 1. Nucleophilic Addition to the Carbon-Oxygen Double bond : The most characteristic reaction of aldehyde and ketone is nucleophilic addition to the carbon-oxygen double bond. General Reaction : Relative reactivity of Aldehydes versus Ketones : Aldehydes are more reactive than Ketones. There are two reasons for this, they are as follows : 1. 1. Steric Factor 2. Electronic factor Steric Factor : With one group being the small hydrogen atom, the central carbon of the tetrahedral product formed from the aldehyde is less crowded and the product is more stable. With ketones two alkyl groups at the carbonyl carbon causes greater steric crowding in the tetrahedral product and make it less stable. Therefore small concentration is present at equilibrium. 2. Electronic Factor : Because alkyl group are electron releasing therefore aldehydes are more reactive on electronic grounds as well. Aldehyde have one electron releasing alkyl group to stablise the partial positive charge on the carbon atom of the carbonyl group. Whereas ketones have two alkyl groups. Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 11 Addition of cyanide : (b) Addition derivatives of ammonia : w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om (a) (i) (ii) HCHO reacts with NH3 differently forming UROTROPINE [hexamethylene tetraamine]. 6HCHO + 4NH3 (CH2)6N4 + 4H2O H2N – G (c) Product H2N – OH Hydroxylamine = N – OH oxime H2N – NH2 Hydrazine = N – NH2 Hydrazone H2N – NHC6H5 Phenylhydrazine = N – NHC6H5 Phenylhydrazone H2N – NHCOCH2 Semicarbazine = NNHCOCH2 Semicarbazone Addition of Alcohols : Acetal Formation (i) (ii) Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 12 Important : (d) Addition of Grignard reagents : Formaldehyde with Grignard Reagent gives 10alcohol, all higher aldehydes with grignard reagent give 20 alcohol and ketones with grignard reagent gives the 30 alcohol. Other Reactions of Aldehyde and Ketones : w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om C9 (a) Oxidation : (i) RCHO or ArCHO Aldehydes (except) benzaldehyde reduce “Fehling’s Solution” (Cu2+ reduced to Cu+) which is an alkaline solution of Cu2+ ion complexed with tetrarate ion. (ii) Example : Tollen’s Test : CH 3 CHO 2Ag( NH 3 ) 2 3OH – CH 3 COO 2Ag 4NH 3 2H 2 O Colourless Solution Silver mirror Fehling Solution CH 3 CHO 2Cu 2 3OH CH 3 COO 2Cu 2H 2O Re d PPt . Tollen’s test is cheifly given by aldehydes. Tollen’s reagent does not attack carbon-carbon double bond. Aldehyde also reduce benedict’s solution (Cu2+ complexed with citrate ion) to Cu+ (b) (i) Ketones with strong oxidants and at high temperature undergo cleavage of C-C bond on either side of carbonyl group. Carbonyl Group after bond cleavage goes with that alkyl group which is of smaller size. (ii) Ketones are also oxidised from cleavage of bond by caro’s acid (H2SO5) or SO 5 peroxybenzoic acid (C6H5CO3H) to esters. RCOR H 2 RCOOR [Bayer’ss [O ] Villiger Oxidation] (c) Haloform Test : (i) Einstein Classes, Methylketones : Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 13 (ii) Hypohalite NaOX (NaOH + X2) cannot only halogenate can also oxidise alcohols (d) Reduction : Reduction to alcohol w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om (a) (e) Reduction to hydrocarbons : (f) Reductive Amination (Discussed under Amines) (g) Cannizzaro reaction : In the presence of an concentrated base i.e. alkali, aldehydes containing no -hydrogens undergo self oxidation and reduction to yield a mixture of an alcohol. (i) (ii) (h) Crossed Cannizzaro reaction : Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 14 (i) Tischenko Reaction : All aldehyde in presence of aluminium ethoxide, Al(OC2H5)3 can be simultaneously oxidised (to acid) and reduced (to alcohols) to form ester. This is called Tischenko reaction and is thus like cannizaro reaction. (j) Distinction Aldehyde and Ketones Test RCHO RCOR w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om S.No. 1. Schiffs reagent magenta colour restored by RCHO no. reaction 2. Tollen’s reagent is reduced by RCHO is not reduced 3. Fehling’s solution is reduced by RCHO (except C6H5CHO) is not reduced -hydroxy, ketones reudce Tollen’s re agent and Fehling’s solution Practice Problems : 1. HBr (a) 2. 3. 4. C2H 5I (b) C2H5OH (c) CHI3 2 (d) (a) aldehyde (b) secondard alcohol (c) alkene (d) tert. alcohol CH3CHO Which statement is incorrect in the case of acetaldehyde and acetone (a) both react with hydroxylamine (b) both react with NaHSO3 (c) both react with hydrazine (d) both reduce ammonical silver nitrate Which of the following undergoes Cannizzaro’s reaction CH3CHO (b) CH3CH2CHO (c) (CH3)2CHCHO (d) HCHO (c) acetone phenol Urotropine is formed by the action of ammonia on (a) 6. NaOH A compound (X) of the formula C3H8O yields a compound C3H6O on oxidation. To which of the following class of compounds could (X) belong (a) 5. Hydrolysis ( X ) ( Y )) I( excess ) ( Z ) Identify (Z) in the reaction series, CH 2 CH 2 acetaldehyde (b) formaldehyde (d) Hydrocarbons are formed when aldehydes and ketones are reacted with amalgamated zinc and conc. HCl. The reaction is called (a) Cannizzaro’s reaction (b) Clemmensen’s reduction (c) Rosenmund’s reaction (d) Tischenko reaction Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 15 7. 8. When acetaldehyde is treated with aluminium ethoxide, it forms (a) ethyl acetate (b) ethyl alcohol (c) acetic acid (d) methyl propionate (c) acetone (d) Chloretone is formed when chloroform reacts with (a) 9. (b) acetaldehyde benzaldehyde Which of the following reagent reacts differently with HCHO, CH3CHO and CH3COCH3 (a) 10. formaldehyde HCN (b) NH2OH (c) C6H5NHNH2 (d) NH3 In the following sequence of reactions, the end product is 2 / H 2SO 4 O] )2 2O CaC2 H (A) Hg (B) [ ((C) Ca ( OH (D) heat (E) (a) 11. acetaldehyde (b) formaldehyde (c) acetic acid (d) acetone In the following sequence of reactions, the end product is 2 w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om / H 2SO 4 [O] HC CH Hg (A) CH 3MgX ((B) (C) [ H 2O ] 12. 13. (a) acetaldehyde (b) isopropyl alcohol (c) acetone (d) ethyl alcohol HCN (a) CH3COOH (b) CH3CHOHCOOH (c) CH3CH2NH2 (d) CH3CONH2 A compound, C5H10O, forms a phenyl hydrazone and gives negative Tollen’s and iodoform tests. The compound on reduction gives n-pentane. The compound A is (a) 14. H O 2 In the following sequence of reactions, the end product is CH 3CHO ( A ) ( B) pentanal (b) pentanone-2 (c) pentanone-3 (d) amyl alcohol CHI3 (d) CH3CHO ethyl acetate (d) acetylene The product Z in the series is Na 2 CO 3 CH 2 CH 2 HBr X Hydrolysis Y I Z 2 ( excess ) (a) 15. 17. methane (b) methanol (a) CH3CHO > CH3COCH3 > CH3COC2H5 (b) C2H5COCH3 > CH3COCH3 > CH3CHO (c) CH3COCH3 > CH3CHO > C2H5COCH3 (d) CH3COCH3 > C2H5COCH3 > CH3CHO (c) (c) To distinguish between 2-pentanone and 3-pentanone which reagent can be used (c) 19. C2H5OH The correct order of reactivity in nucleophilic addition reaction CH3CHO, CH3COC2H5 and CH3COCH3 is (a) 18. (b) If formaldehyde and KOH are treated together, we get (a) 16. C2H 5I NaOH/I2 K2Cr2O7/H + (b) Tollen’s reagent (d) Zn–Hg, HCl CH3CH = CHCHO is oxidised to CH3 – CH = CHCOOH, using oxidising agent as (a) alkaline KMnO4 (b) K2Cr2O7/conc. H2SO4 (c) ammonical AgNO3 (d) dilute HNO3 m-chloro benzaldehyde on reaction with conc. KOH at room temperature gives (a) potassium m-chloro benzoate and m-hydroxy benzaldehyde (b) m-chloro benzyl alcohol and m-hydroxy benzaldehyde (c) m-chloro benzyl alcohol and m-hydroxy benzyl alcohol (d) m-chloro benzyl alcohol and potassium m-chloro benzoate Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 16 20. (a) 2, 4-dinitrophenyl hydrazine (b) benedict reagent (c) I2 and Na2CO3 (d) aqueous solution of NaHSO3 Best starting material to synthesize 2-methyl-2-butenoic acid is (a) (b) (c) (d) CH3CH2CH2CHO w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om 21. The reagent which can be used to distinguish acetophenone from benzophenone is : 22. X and Y can be distinguished by : (a) 23. silver-mirror test(b) iodoform test (c) both (d) CH3 C CCl3 (b) CH 3 C CH 2 I CH 3 C CH 2Cl (d) none Which of the following will give haloform test O || (a) (c) | OH all || O [Answers : (1) c (2) b (3) d (4) d (5) b (6) b (7) a (8) c (9) d (10) d (11) c (12) b (13) c (14) c (15) b (16) a (17) a (18) a (19) d (20) c (21) c (22) c (23) d] Carboxylic Acids and Derivatives C10 Common name of carboxylic acids : 1. CH3CH2CH2CH2COOH valeric acid 3. Malonic acid; 5. maliec acid 6. Einstein Classes, 2. oxalic acid 4. ; Succinic acid Fumaric acid adipic acid Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 17 7. or 8. 9. 12. 14. 16. 18. 19. 20. C11 O-Toluic acid 11. Phathalic acid w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om 10. CH2 = CH – COOH (acrylic acid) Isophthalic acid Salicylic acid 13. Terphthalic acid 15. Anthranilic acid 17. CH3 – CH = CH – COOH (crotonic acid) (Pyruvic acid) Methods of preparation of carboxylic acid : (a) By acid hydrolysis of cyanidies (b) By the use of Grigrand Reagent Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 18 (c) By oxidation method (i) Oxidation of alcohols (10) (ii) Oxidation of aldehyde (iii) Oxidation of ketones w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om Iodoform Test : (d) i ) Alkaline KMnO 4 Oxidation of alkenes and alkynes R CH CH R ( 2RCOOH ( ii ) / H (i )O R CH CH R 3 2RCOOH ( ii ) H 2 O Practice Problems : 1. Cyanohydrin of which of the following gives lactic acid on hydrolysis (a) acetone (b) acetaldehyde (c) propanal (d) HCHO [Answers : (1) b] C12 Chemical Properties of Carboxylic Acids : (a) Carboxylic acid undergo nucleophilic substitution reaction (i) Formation of amide from carboxylic acid (ii) Formation of Acyl chloride (iii) Formation of esters (b) Formation of anhydride : (c) Schmidt reaction : (d) HVZ reaction : (e) Reduction of caboxylic acid : CH 3 COOH LiAlH 4 CH 3 CH 2 OH (f) CaO Formatin of alkane : CH 3 COOH NaOH CH 4 (g) ( OH ) Formatin of Salts : CH 3 COOH Ca 2 (CH 3 COO ) 2 Ca effect of heating on salts : (CH 3 COO ) 2 Ca CH 3 COCH 3 (h) i ) KOH Kolbe electrolysis : CH 3 COOH ( CH 3 CH 3 ( ii ) Electrolysis (i) Acidic character : CH 3 COOH NaHCO 3 CH 3 COONa CO 2 H 2 O Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 19 Practice Problems : 1. 2. Which of the following will not undergo HVZ reaction (a) 2, 2-dimethyl propanoic acid (b) propanoic acid (c) acetic acid (d) 2-methyl propanoic acid Amongst the acids (a) CH CCOOH (b) CH2 = CHCOOH and (c) CH3CH2COOH, the acid strength follows the sequence (a) 3. (a) > (b) > (c) (b) (a) < (b) < (c) (c) (a) = (b) = (c) (d) (a) = (b) < (c) Cl 2 CH 3CH 2 COOH (A) Alc .KOH (B) The compound (B) is P (a) CH3CH2OH (b) CH3CH2CN (c) CH2 = CHCOOH (d) CH3CHClCOOH Formic acid (a) is immiscible with water (b) reduces ammonical silver nitrate (c) is a weak acid nearly three and a half times weaker than acetic acid (d) is prepared by heating potassium formate 5. Strongest acid out of CH3CO2H, CH2 = CHCO2H, w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om 4. (a) CH3CO2H (c) —CO2H —CO2H (b) CH2 = CHCO2H (d) equal Ka [Answers : (1) a (2) a (3) c (4) b (5) c] CARBOXYLIC ACID DERIVATIVES C13A Structures : Closely related to the cabroxylic acids and to each other are a number of chemical families known as functional derivative of carboxylic acids : Acid chlorides, anhydrides, amides and esters. Acid chlorides, anhydrides, amides and esters. These derivatives are compounds in which the –OH of a carboxylic group has been replaced by –Cl, –OOCR, –NH2 or OR They all contain acyl group C13B Physical properties : The presence of group makes the acid derivatives polar compounds. Acid chlorides and anhydrides and esters have boiling point is same as of aldehydes and ketones of corresponding molcular weight. Amides have quite high boiling points because they are capable of strong intermolecular hydrogen bonding. Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 20 The borderline for solubility in water ranges from three to five carbons for the esters to five to six carbons for the amides. The acid derivatives are soluble in usual organic solvents. Volatile esters have pleasant, rather chracteristic odours; they are often used in the praparation of perfumes and artificial flavoring. Acid chlorides have sharp, irritating odours, at least partly due to their ready hydrolysis to HCl and carboxylic acids C14A Nucleophilic acyl substitution : w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om Each derivative is nearly always prepared - directly or indirectly from carboxylic acids, and can be readily converted into the carboxylic acid by simple hydrolysis. The derivatives of carboxylic acids, like the acids themselves, contain the carbonyl group, . Here, too, as in aldehydes and ketones, the carbonyl group performs two functions : (a) It provides a site for nucleophilic attack (b) It increases the acidity of hydrogents attached to the alpha carbon. Acyl compounds i.e. Carboxylic acids and their derivatives, typically undergo nucleophilic substitution in which – OH, – Cl, – OOCR, or – OR is replaced by some other basic group. Substitution takes place much more readily than at a saturated carbon atom; many of these substitution do not take at all in the absence of carbonyl group e.g. replacement of – NH2 by – OH. – W = – OH, – Cl, – OOCR, – NH2, – OR Let us discuss now properties of acyl compounds. Both electronic and steric factors make the carbonyl carbon suceptible to nucleophilic attack. (a) The tendency of oxygen to acquire the negative charge. (b) The relatively unhindered transition state leading from the trigonal reactant to the tetrahedral intermediate. These factors make acyl compounds, too suceptible to nucleophilic attack. It is the second step of reaction that acyl compounds differ from aldehydes and ketones. The tetrahedral intermediate from an aldehyde/ketone compound gains a proton and the result is addition. The tetrahedral intermediate from an acyl compound ejects the :W group, returning to a trigonal compound and thus result in substitution. Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 21 C15A Acid Chlorides : Acid chlorides are prepared from the corresponding acids by reaction with SOCl2, PCl5 or PCl3 as already discussed. C15B Reactions : Acid chlorides are the most reactive of the derivatives of carboxylic acids. 1. Like other derivatives it also undergo nucleophilic substitution reaction. Chlorine is expelled as chloride and its place is taken by some other basic group. Conversion into acids, hydrolysis : w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om (a) (b) Conversion into amides : (c) Conversion into Esters : Acid chloride is added in portions to a mixture of the hydroxy compound and a base usually aq. NaOH or pyridine. Base serves not only to neutrilize the HCl evolved but also to catalyze the reaction. 2. Formation of Ketones. Friedel - Craft’s acylation : 3. Formation of ketones, Reaction with organo copper compounds : 4. Formation of aldehydes by reduction : RCOCl or ArCOCl 3 RCHO or ArCHO 1. Sodium acetate + acetyl chloride gives LiAlH ( OBU t ) (a) CH3COOH (b) sodium formate (c) acetic anhydride (d) acetone (c) C16A Acid Anhydrides Preparation : (i) Acetic anhydride is prepared by the reaction of acetic acid with ketene CH2 = C = O, which itself is prepared by high teperature dehydration of acetic acid. (ii) In contrast to monocarboxylic acids, certain dicarboxylic acids yield anhydrides on simple heating. In those cases where five or six membered ring is produced. Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 22 (a) w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om (b) Ring size is crucial : with adipic acid, e.g. anhydride formation would produce seven-membered ring and does not take place. Instead carbon dioxide is lost and cyclopentanone is produced (a five membered ring is formed) : C16B Reactions of Acid Anhydrides : (i) Conversion into acids. Hydrolysis : Example : (ii) Conversion into amides. Ammonolysis : Example : (iii) Conversion into esters : Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 23 (iv) Formation of Ketone : Friedel craft acylation w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om Amides C17A Preparation : In the laboratory method of preparation of amide includes its preparation from acid chloride with ammonia, acid anhydride with ammonia. In industry they are prepared by heating ammonium salts of carboxylic acids. C17B Reaction of Amides : 1. Hydrolysis : 2. Conversion into nitrile : 3. Conversion into imides : Example : 4. Hoffmann degradation of amides : Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 24 Practice Problems : 1. The end product in the followin series of reaction is 2O5 CH 3COOH NH 3 ( A ) heat ( B) P (C) 2. (a) CH4 (b) CH3OH (c) acetonitrile (d) ammonium acetate NH PO 2 5 In a reaction, ( A ) 3 (B) heat (C) C 2 H 5 CN (A), (B) and (C) are : (a) CH3COOH, CH3COONH4 and CH3CONH2 (b) CH3COCl, CH3CONH2 and CH3COONH4 (c) C2H5COOH, C2H5COONH4 and C2H5CONH2 (d) C2H5COONH4, C2H5CONH2 and C2H5COOH w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om [Answers : (1) c (2) c] Esters : C18A Preparation of Esters : 1. From acids : Reactivity of R OH is 10 > 20 > 30 similarly > 10 > 20 > 30 Example 2. From Acid Chloride or anhydride : 3. Formation of cyclic esters (Lactone) A hydroxy acid is both alcohol and acid. In those cases where five or six membered ring can form intermolecular esterification occurs. Thus or hydroxy acid looses water spontaneously by yield of cyclic ester known as lactone. Treatment with base (OH–) rapidly opens the lactone ring. Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 25 C18B Reactions of Esters : Conversion into acids and acid derivatives 2. Conversion into amides w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om 1 CH3COOC2H5 + NH3 CH3CONH2 + C2H5OH Treatment of an ester with ammonia, generally in ethylalcohol solution yield the amides. This reaction involved the nucleophilic attack by a base, ammonia, on the electron-deficient carbon; the alkoxy group, OR' is replaced by – NH2. 3. Conversion into esters : Transesterfication : Acid is H2SO4 or dry HCl Base alkoxide ion generally used. 4. Reactions with Grignard Reagent : 5. Reduction to alcohols : (a) Catalytic hydrogenation : Hydrogenolysis CuO, CuCr O 2 4 RCOOR 2H 2 RCH 2OH R' OH 0 250 C (b) 6. 10 alcohol . ether Chemical Reduction : R COOR LiAlH 4 Anhyd RCH 2 OH R OH Reaction with carbanions : Clasien Condensation : R Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 26 Example : 7. Crossed Clasien Condensation : w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om Like a crossed aldol condensation, a crossed clasien condensation is also possible only when one of the reactants has no -hydrogens and thus is incapable of undergoing self condensation. PHENOLS C19A Structure and Nomenclature of Phenols : Compounds that have a hydroxyl group directly attached to benzene ring are called phenols. Thus phenol is specific name of hydroxy benzene Compounds that have a hydroxyl group attached to a polycyclic benenoid ring are chemically similar to phenols, but they are called napthols and phenanthrols, e.g. C19B Physical Properties of Phenols : The presence of hydroxy groups in the molecules of phenols means that phenols are like alcohols in being able to form strong intermolecular hydrogen bonds. This hydrogen bonding causes phenols to be associated and therefore to have higher boiling points than hydrocarbons of the same molecular weight. Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 27 C20A Synthesis of Phenols : Laboratory Synthesis : The most important laboratory synthesis of phenols is by hydrolysis of arenediazonium salts. This method is highly versatile and the conditions required for the diazotisation step and the hydrolysis step are mild. 1. General Reaction : w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om Specific Example : Industrial Synthesis : 2. Hydrolysis of Cholorobenzene (Dow Process) : (The mechanism for the reaction probably involves benzyne intermediate) 3. Alkali Fusion of Sodium benzene sulfonate : Sodium benzene sulfonate is melted (fused) with sodium hydroxide at 3500C to produce sodium phenoxide acidification then yields phenol. 4. From Cumene Hydroperoxide : I II This cumene is oxidized to cumene hydrolperoxide Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 28 Finally, when treated with 10% sulfuric acid, cumene hydroperoxide undergoes a hydrolytic rearrangement that yields phenol and acetone. C20B Chemical Properties of Phenol : 1. Reaction of Phenol as Acid : Strength of phenols as acids : Although phenols are structurally similar to alcohols, they are much stronger acids. The pKa values of most alcohols are of the order of 18. However the pKa values of phenols are smaller than 11. w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om Let us compare two superficially similar compounds cyclohexanol ane phenol. Although phenol is weak acid when compared with carboxylic acid such as acetic acid (pKa = 4.75) phenol is much stronger than cyclohexanol by a factor of 8. Phenols are more acidic than cyclohexanol because of following reasons : Phenoxide ion is more resonance stabilized than phenol. Resonance structures of phenoxid ion do not involve charge separation. No resonance structure can be written for cyclohexanol and its anion of course. The benzene ring of phenol acts as if it were as electron withdrawing group when we compare it with cyclohexanol. That causes –OH oxygen to be more positive. Reason : Carbon atom that bears hydroxyl group in phenol is sp2 hybridized, whereas in cyclohexanol sp3 bybridised. Greater the S– characted more electronegative the carbon. Thus carbon of benzene is more electronegative than cyclohexanol. Because phenols are more acidic than water, the following reaction goes almost completion. The reaction between cyclohexanol and NaOH does not occur to significant extent as H2O is stronger acid than 1-wexanol. Acidity order of Phenols : (a) Einstein Classes, (b) Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 29 (c) (d) w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om (e) Distinguishing and separating phenols from alcohols and carboxylic acids : 1. Phenols dissolve in aqueous sodium hyroxide whereas most alcohols with six carbon atoms or more do not. Thus we can distinguish them. 2. Alcohols with five carbon atoms are more or less soluble in NaOH but do not form appreciable amount of sodium alkoxide. 3. Most phenols are not solible in aqueous sodium bicarbonate, but carboxylic acids are soluble. C21 Other reactions of the O – H Group of Phenols : 1. Phenols react with carboxylic acid anhydrides and acid chlorides to form esters. Thest reactions are similar to alcoholic as we have already discussed in alcohols. 2. Phenols in the Williamson Synthesis : Because phenols are more acidic than alcohols they can be converted to sodium phenoxide through the use of sodium hydroxide (rather than use of sodium metal, the reagent that convert alcohols to alkoxide ion). (a) X General Reaction : ArOH NaOH ArO N a R ArOR NaX [ X Cl , Br , I ] (b) Cleavage of Alkyl-Aryl Ether : conc . HX HX C6 H 5 O R C6 H 5 OH no rxn. RX heat 3. Reactions of the Benzene ring of Phenol : (a) Bromination : The hydroxyl group is a powerful activating group and an ortho-para director in electrophilic substitution. Phenol itself react with Br2 in aqueous solution to yield 2, 4, 6-tribromophenol. Note that a Lewis acid is not required for the bromination of Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 30 this highly activated ring. Monobromination of phenol can be achieved by carrying out the reaction in carbon disulfide (CS2) at low temperature. Conditions that reduce the electrophilic activity of bromine. The major product is the para isomer. w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om (b) 4. (a) Nitration : Phenol react with dilute nitric acid to yield a mixture o- and p-nitrophenol Although the yield is relatively low (because of oxidation of ring). The ortho and para isomers can be separated by steam distillation. o-Nitrophenol is more volatile isomer because its intramolecular hydrogen bonding. p-Nitrophenol is less volatile because intermolecular H-bonding causing association among molecules. Thus o-nitrophenol passes over steam and p-Nitrophenol remain in the distillation flask. (b) Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 31 Sulfonation : Phenol reacts with concentrated sulfuric acid to yield mainly o-sulphonated product if the reaction is carried out at 250C and mainly the para substituted product if the reaction is at 1000C. 6. Kolbe’s Reaction : The phenoxide ion is even more suceptible to electrophilic aromatic substitution, then phenol itself. w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om 5. High reactivity of phenoxide ion is used in a reaction called as kolbe reaction. In kolbe reaction carbon dioxide act as the electrophile. Reaction of salicylic acid with acetic anyhydride yields widely used pain reliver aspirin. 7. The Clasien rearrangement : Clasien rearrangement can also take place when allyl vinyl ether are present 8. Diel Alder reaction is also pericyclic reaction : 9. Quinones : Oxidation of hydroquinone gives quinone Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 32 Reimer-Tiemann Reaction : 11. Fries rearrangement : w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om 10. 1. 2. 3. 4. Rearrangement involves RCO+, which then attacks the ring. Practice Problems : When phenol is distilled with zinc dust, the main product is (a) biphenyl (b) benzene (c) benzaldehyde (d) phenolphtalein When sodium benzene sulphonate is fused with sodium hydroxide (solid), the product formed is (a) benzene (b) phenol (c) benzene triphenol (d) none of these Which of the following acids is strongest (a) C6H5SO3H (b) CH3COOH (c) C6H5COOH (d) (COOH)2 Phenol is less acidic then (a) p-nitrophenol (b) ethanol (c) cresol (d) benzyl alcohol (i ) O 2 ( (X) and (Y) ii ) H O , H 5. Cumene 6. (X) and (Y) respectively are (a) toluene, propene (c) phenol, acetone In the following compounds 2 7. toluene, propylchloride phenol, acetaldehyde the order of acidity is (a) III > IV > I > II (b) I > IV > III > II (c) II > I > III > IV (d) IV > III > I > II When phenol reacts with benzene diazonium chloride, the product obtained as (a) phenyl hydrazine (b) p-amino azobenzene (c) phenol hydroxylamine (d) p-hydroxy azobenzene Zinc 8. (b) (d) Conc . HNO 3 Zn Phenol distillati ( A ) Conc ( B )) NaOH (C) . In the above reaction, compounds (A), on . H SO at 60 0 2 4 (B) and (C) are (a) benzene, nitrobenzene and aniline (b) benzene, dinitrobenzene and m-nitroaniline (c) toluene, nitrobenzene and m-toluidine (d) benzene, nitrobenzene and hydrazobenzene [Answers : (1) b (2) b (3) a (4) a (5) c (6) d (7) d (8) d] Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 33 INITIAL STEP EXERCISE 1. Identify (Z) in the series, 6. . H 2SO 4 Br2 C3H 7 OH Conc (X) (Y ) 0 In the following sequence of reactions, the end product is on g agent CH 3CHO Condensati (A ) Dehydratin (B) 170 C mild alkali of Excess ( Z) Alc. KOH (a) 7. (b) (d) CH3 – C CH 8. 2. When ethyl benzoate is hydrolysed with aqueous alkali, the products present in the medium are (a) (b) (c) (d) 3. (c) 4. C6H5COOH and C2H5O— C6H5COO— and C2H5OH C6H5COO— and C2H5O— (b) (c) (d) crotonaldehyde (c) paraldehyde (d) metaldehyde Which of the following reaction is a condensation reaction (a) HCHO Paraformaldehyde (b) CH3CHO Paraldehyde (c) CH3COCH3 Mesityl oxide (d) CH2 = CH2 Polyethylene 9. A compound A has molecular formula C2Cl3OH. It reduces Fehling’s solution and on oxidation gives a monocarboxylic acid. A is obtained by the action of Cl2 on ethyl alcohol. The compound A is (a) chloroform (b) chloral (c) trichloro ethanol (d) trichloro acetic acid Salicylic acid on heating with soda lime forms (b) 4 (a) benzene (b) phenol 3 (d) 2 (c) benzyl alcohol (d) benzoic acid 10. Out of butane, butanol-1, butanal and butanone, the decreasing order of their boiling point is CH3CH2CH2OH (a) butane > butanol > butanal > butanone CH3CH2CH(OH)CH3 (b) butanol > butane > butanal > butanone CH3CH(OH)CH2CH2CH3 (c) butanone > butanal > butanol > butane (CH3)2C(OH)CH2CH3 (d) butanol > butanal > butanone > butane Which aromatic acid among the following is weaker than simple benzoic acid (a) (b) 5 An alcohol on oxidation is found to give CH3COOH and CH3CH2COOH. The structure of the alcohol is (a) 5. C6H5COOH and C2H5OH How many isomers of C5H11OH will be primary alcohols : (a) aldol w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om (c) (a) heat 11. (b) 12. (c) Einstein Classes, (d) The alkene which on ozonolysis yields only acetone is (a) CH2 = CH2 (b) CH3 – CH = CH2 (c) (CH3)2C = C(CH3)2 (d) CH3CH = CHCH3 In the reaction CH3CHO + HCN CH3CHOHCN, a chiral centre is produced. The product is (a) meso compound (b) laevorotatory (c) dextrorotatory (d) racemic mixture Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 34 13. Leaving tendency of the following in increasing order : 19. Which of the following reactions is expected to readily give a hydrocarbon product in good yield (a) is RCOOK Electrolys (b) Br2 RCOOAg (c) Cl 2 CH 3CH 3 hv 2 H 5 OH (CH 3 ) 3 C Cl C (d) 15. 16. 17. VI < V < III < II < IV < I 20. (b) I < II < III < VI < V < IV When propionic acid is treated with aqueous NaHCO3, CO2 is liberated. The ‘C’ of CO2 comes from (c) I < III < V < II < IV < VI (a) methyl group (d) can’t be decided (b) carboxylic acid group (c) methylene group (d) bicarbonate w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om 14. (a) Formylchloride has not been prepared so far. Which can function as formylchloride in formylation (a) HCHO + HCl (b) HCOOCH3 + HCl Which will liberate ammonia when boiled with NaOH solution (c) CO + HCl (a) ethyl amine (b) acetamide (d) HCONH2 + HCl (c) aniline (d) all 21. Formic acid is obtained when 22. (a) calcium acetate is heated with conc. H2SO4 (b) glycerol is heated with oxalic acid (c) acetaldehyde is oxidised with K2Cr2O7 and H2SO4 (d) calcium formate is heated with calcium acetate Formic acid and formaldehyde can be distinguished by treating with (a) Benedict’s solution (b) Tollen’s reagent (c) Fehling’s solution (d) NaHCO3 23. 24. 25. In the reaction PI 3 C 2 H 5 OH (A ) KCN (B) Hydrolysis (C) The product (C) is 18. (a) acetic acid (b) formic acid (c) oxalic acid (d) propionic acid 26. Acetyl chloride is not obtained from acetic acid by the action of (a) CHCl3 (b) SOCl2 (c) PCl3 (d) PCl5 Main product of the reaction CH 3 CONH 2 + HNO2 is (a) CH3NH2 (b) CH3CH2NH2 (c) CH3COOH (d) CH3OH Urea is a (a) monobasic acid (b) dibasic acid (c) monoacid base (d) diacid base Al ( OC H ) 5 3 CH3COOCH2CH3. This 2CH3CHO 2 reaction is called (a) Cannizzaro’s reaction (b) Aldol condensation (c) Claisen’s reaction (d) Tischenko reaction Explain the reactivity of acyl compounds in the order (a) acid chloride > amide > anhydride > ester The above reaction is called (b) acid chloride > anhydride > ester > amide (a) HVZ reaction (c) ester > acid chloride > anhydride > amide (b) Hunsdiecker reaction (d) ester > anhydride > acid chloride > amide (c) Schmidt reaction (d) Decarboxylation reaction H SO ( conc .) 2 4 RNH2 + CO2 + N2 RCOOH + N3H Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 35 28. 29. 30. Artificial oil of bitter almonds or oil of Mirabane is the name given to (a) chlorobenzene (b) benzaldehyde (c) aniline (d) nitrobenzene 35. OAc, OMe, OSO2 Me, SO 2 CF3 ( I) Which does not have a carboxyl group (a) picric acid (b) ethanoic acid (c) aspirin (d) benzoic acid Phenols do not react with (a) sodium bicarbonate (b) sodium hydroxide (c) potassium hydroxide (d) ferric chloride 36. In the reaction, 37. C 6 H 5CH 2 Cl Aq . NaOH (A) Oxidation (B) , Cu ( NO 3 ) 2 (B) is (a) (c) 31. (b) (c) (d) 32. (b) (c) (d) 34. (b) phenol toluene (d) benzaldehyde aldol condensation 38. 39. benzoin condensation ( II ) ( III ) ( IV ) the order of leaving group ability is (a) I > II > III > IV (b) IV > III > I > II (c) III > II > I > IV (d) II > III > IV > I Benzyl alcohol is obtained from benzaldehyde by (a) Wurtz reaction (b) Cannizzaro’s reaction (c) Perkin reaction (d) Claisen reaction Anhyd .AlCl 3 (X) + HCl C6H6 + CO + HCl The compound (X) is (a) C6H5CHO (b) C6H5COOH (c) C6H5CH2Cl (d) C6H5CH3 Which of the following is the weakest acid (a) benzene sulphonic acid (b) benzoic acid (c) benzyl alcohol (d) phenol In the Cannizzaro’s reaction given below 2Ph CHO OH Ph CH 2OH PhCO 2 Perkin reaction the slowest step is (a) attack of OH— at the carbonyl group (b) the transfer of hydride to the carbonyl group (c) the abstraction of proton from the carboxylic acid (d) the deprotonation of Ph–CH2OH Wurtz reaction Benzaldehyde when refluxed with aqueous alcoholic KCN forms (a) 33. benzoic acid The reaction involving condensation of acetic anhydride with an aromatic aldehyde by a carboxylate ion is an example of (a) In the following groups, w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om 27. benzoin benzene phenyl cyanide phenyl isocyanide The reaction, C6H5CHO + CH3CHO C6H5CH = CHCHO is called : (a) benzoin condensation (b) Claisen condensation (c) Perkin reaction (d) Cannizzaro’s reaction Cannizzaro’s reaction is not given by (a) trimethyl acetaldehyde (b) acetaldehyde (c) benzaldehyde (d) formaldehyde Einstein Classes, 40. C6 H 5OH ClOCCH 3 C 6 H 5OOCCH 3 NaOH ( aq .) 41. 42. The above reaction is an example of (a) acetylation (b) benzoylation (c) Schotten-Baumann reaction (d) Reimer-Tiemann reaction Phenol on standing in air develops a red colour due to formation of (a) cyclohexane (b) resorcinol (c) phenoquinone (d) quinol Benzoic acid gives benzene on being heated with X and phenol gives benzene on being heated with Y. Therefore X and Y are respectively (a) soda lime and copper (b) zinc dust and sodium hydroxide (c) zinc dust and soda lime (d) soda lime and zinc dust Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 36 43. ( i ) CHCl / NaOH Salicyladehyde Phenol 3 44. ( ii ) H This reaction is known as (a) Gattermann aldehyde synthesis (b) Duff reaction (c) Perkin reaction (d) Reimer-Tiemann reaction Phenol on treatment with dil HNO3 gives (a) picric acid (b) o- and p-nitro phenols (c) o- and m-nitro phenols (d) p- and m- nitro phenols FINAL STEP EXERCISE 2. A natural compound (X), C4H8O2, reduces Fehling’s solution, liberates hydrogen when treated with sodium metal and gives a positive iodoform test. The structure of (X) is (b) (a) (c) CH3CHOHCH2CHO w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om 1. (b) HOCH2CH2CHO (c) CH3COCH2CHO (d) CH3COCH2CH2OH (d) none is correct In a cannizzaro’s reaction, the intermediate that will be the best hydride donar is 4. cannizzair o X and Y (Y is alcohol, D is deuterium) X and Y will have structure : (a) (a) (b) (b) (c) (c) (d) 5. (d) none is correct Consider reduction of 2-butanone NaBD 4 B 2 butanone NaBD 4 A D 2O H 2O NaBD4 3. product X CH3CH = CH2 HO / OH 2 2 X is : (a) A, B and C are : (a) Einstein Classes, in all cases Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 37 (b) , 8. , (c) propane (d) ethyl methyl ether The major product obtained when 3-phenyl-1, 2-propane-diol is heated with H2SO4 is (a) C6H5 – CH2 – CO – CH3 (b) C6H5 – CH2 – CH2 – CHO (c) C6H5 – CH2 – CH = CH2 (d) 9. , (a) 2-pentanone and 3-pentanone (b) 2-pentanone and 3-methyl-2-butanone (c) 2-pentanone and pentanal (d) 3-pentanone and 3-methyl-2-butanone w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om (c) A carbonyl compound with molecular weight 86, does not reduce Fehling’s solution but forms crystalline bisulphite derivatives and gives iodoform test. The possible compounds can be , 10. In the Cannizzaro’s reaction given below, (d) 2Ph CHO OH PhCH 2 OH PhCOO in all cases the slowest step is 6. The reaction of CH3CH = CH — (a) the attack of OH— at the carbonyl group (b) the transfer of hydride to the carbonyl group (c) the abstraction of proton from the carboxylic acid (d) the deprotonation of Ph–CH2OH —OH with HBr gives : (a) CH3CHBrCH2 — —OH 11. (b) (c) (d) 7. CH3CH2CHBr— —OH CH3CHBrCH2— —Br CH3CH2CHBr— The reaction of with a mixture of Br2 and KOH gives R — NH2 as a product. The intermediates involved in this reaction are (a) (b) R—N=C=O (c) R — NHBr —Br The product (D) in the following sequence of reaction is : (d) ( aq ) Na C 2 H 4 HBr (A) NaOH (B) ( 3I (C) CH (D) (a) butane (b) ethane Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 38 Which of the following carboxylic acid undergo decarboxylation easily (a) C6H5COCH2COOH (b) C6H5COCOOH (c) (d) ANSWERS (INITIAL STEP EXERCISE) 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. c c b c c b c b b d c 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. d a c b d d c a d b a 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. c c d b d a a d c a b 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om 12. b b b a c b a c d d b ANSWERS (FINAL STEP EXERCISE) 1. 2. 3. 4. 5. 6. Einstein Classes, a c b a b b 7. 8. 9. 10. 11. 12. d d b b b a Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com COO – 39 TEST YOURSELF 2. 3. 4. In alcohol 10, 20 and 30 cann’t be distinguish by CH CHO hydrolysis R Mg X 3( A ) (B) . (a) Catalyst dehydrogenration Compound B in above sequence of reaction is (b) Victor meyer’s test (a) Carboxylic acid (c) Lucas reagent test (b) Primary alcohol (d) can be distinguish by all (c) Secondary alcohol (d) Tertiary alcohol The number of isomers represented by molecular formula C4H10O is (a) 3 (b) 4 (c) 7 (d) 10 10. The reaction, H SO RCOOH N 3 H 2 4 RNH 2 CO 2 N 2 Conc. LiAlH4 converts acetic acid into is called (a) acetaldehyde (b) ethane (a) (c) ethyl alcohol (d) methyl alcohol (b) Hoffmann’s reaction RONa + XR ROR NaX is (c) Schmidt reaction (a) (d) Decarboxylation reaction (b) (c) (d) 5. 9. HVZ reaction w E w IN w S .e T in E st IN ei C nc L la AS ss S es ES .c om 1. Wurtz reaction Williamson synthesis Reimer-tiemer reaction Tischenko reaction The ether . When treated with cold HI produces (a) (b) (c) (d) 6. 2C6H5OH C6H5I and C6H5CH2OH C6H5CH2I and C6H5OH General formula of both aldehydes and ketones is (a) (c) 7. 2C6H5CH2I CnH2n + 2O (b) CnH2nO CnH2n – 2O (d) CnH2n + 4O The appropriate reagent for the following transformation is : (a) (c) 8. Zn(Hg)/HCl (b) NH2NH2/OH– H2/Ni– (d) NaBH4 The Cannizzaro’s reaction is not given by (a) trimethyl acetaldehyde (b) acetaldehyde (c) benzaldehyde 1. d 6. b (d) formaldehyde 2. c 7. b 3. c 8. b 4. b 9. c 5. d 10. c Einstein Classes, ANSWERS Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., New Delhi -18 Ph. : 9312629035, 8527112111, E-mail [email protected], www.einsteinclasses.com