CARBOXYLIC ACIDS AND DERIVATIVES - Einstein …einsteinclasses.com/Carboxylic Acids_Ac_De.pdf · CCAD – 3 Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri

CCAD – 1

Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri Extn., Outer Ring Road

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CARBOXYLIC ACIDS AND DERIVATIVES

C1 Common name of carboxylic acids :

1. CH3CH

2CH

2CH

2COOH valeric acid 2. oxalic acid

3. Malonic acid; 4. Succinic acid

5. maliec acid ; Fumaric acid

6. adipic acid

7. or

8. 9. CH2 = CH – COOH (acrylic acid)

10. O-Toluic acid 11. Phathalic acid

12. Isophthalic acid 13. Terphthalic acid

14. Salicylic acid 15. Anthranilic acid

16. 17.

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18.

19. CH3 – CH = CH – COOH (crotonic acid)

20. (Pyruvic acid)

C2 Methods of preparation of carboxylic acid :

(a) By acid hydrolysis of cyanidies

(b) By the use of Grigrand Reagent

(c) By oxidation method

(i) Oxidation of alcohols (10)

(ii) Oxidation of aldehyde

(iii) Oxidation of ketones

Iodoform Test :

(d) Oxidation of alkenes and alkynes RCOOH2RCHCHRH/)ii(

KMnOAlkaline)i( 4

RCOOH2RCHCHROH)ii(

O)i(

2

3

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]

C3 Chemical Properties of Carboxylic Acids :

(a) Carboxylic acid undergo nucleophilic substitution reaction

(i) Formation of amide from carboxylic acid

(ii) Formation of Acyl chloride

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(iii) Formation of esters

(b) Formation of anhydride :

(c) Schmidt reaction :

(d) HVZ reaction :

(e) Reduction of caboxylic acid : OHCHCHCOOHCH 23LiAlH

34

(f) Formatin of alkane : 4CaONaOH

3 CHCOOHCH

(g) Formatin of Salts : Ca)COOCH(COOHCH 23)OH(Ca

32

effect of heating on salts : 3323 COCHCHCa)COOCH(

(h) Kolbe electrolysis : 33

isElectrolys)ii(

KOH)i(3 CHCHCOOHCH

(i) Acidic character : OHCOCOONaCHCOOHCH 223NaHCO

33

Practice Problems :

1. 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

2. Amongst the acids (a) CH CCOOH (b) CH2 = CHCOOH and (c) CH

3CH

2COOH, the acid strength

follows the sequence

(a) (a) > (b) > (c) (b) (a) < (b) < (c) (c) (a) = (b) = (c) (d) (a) = (b) < (c)

3. )B()A(COOHCHCHKOH.Alc

P

Cl23

2 The compound (B) is

(a) CH3CH

2OH (b) CH

3CH

2CN

(c) CH2 = CHCOOH (d) CH

3CHClCOOH

4. 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 CH3CO

2H, CH

2 = CHCO

2H, —CO

2H

(a) CH3CO

2H (b) CH

2 = CHCO

2H

(c) —CO2H (d) equal Ka

[Answers : (1) a (2) a (3) c (4) b (5) c]

CARBOXYLIC ACID DERIVATIVES

C4A Structures : Closely related to the cabroxylic acids and to each other are a number of chemicalfamilies known as functional derivative of carboxylic acids : Acid chlorides, anhydrides, amides andesters. 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 RO

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They all contain acyl group

C4B 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 ofcorresponding molcular weight.

Amides have quite high boiling points because they are capable of strong intermolecular hydrogenbonding.

The borderline for solubility in water ranges from three to five carbons for the esters to five to sixcarbons 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 ofperfumes and artificial flavoring.

Acid chlorides have sharp, irritating odours, at least partly due to their ready hydrolysis to HCl andcarboxylic acids

C5 Nucleophilic acyl substitution :

Each derivative is nearly always prepared - directly or indirectly from carboxylic acids, and can bereadily 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 nucleophilicsubstitution 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 thesesubstitution do not take at all in the absence of carbonyl group e.g. replacement of – NH

2 by – OH.

– W = – OH, – Cl, – OOCR, – NH2, – RO

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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 thetetrahedral intermediate. These factors make acyl compounds, too suceptible tonucleophilic 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 isaddition.

The tetrahedral intermediate from an acyl compound ejects the :W group, returning to a trigonalcompound and thus result in substitution.

C6A Acid Chlorides : Acid chlorides are prepared from the corresponding acids by reaction with SOCl2,

PCl5 or PCl

3 as already discussed.

C6B 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 aschloride and its place is taken by some other basic group.

(a) Conversion into acids, hydrolysis :

(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 thereaction.

2. Formation of Ketones. Friedel - Craft’s acylation :

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3. Formation of ketones, Reaction with organo copper compounds :

4. Formation of aldehydes by reduction : RCOCl or ArCOCl 3)tOBU(LiAlH

RCHO or ArCHO

1. Sodium acetate + acetyl chloride gives

(a) CH3COOH (b) sodium formate

(c) acetic anhydride (d) acetone

(c)

C7A 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 simpleheating. In those cases where five or six membered ring is produced.

(a)

(b)

Ring size is crucial : with adipic acid, e.g. anhydride formation would produce seven-membered ringand does not take place. Instead carbon dioxide is lost and cyclopentanone is produced (a fivemembered ring is formed) :

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C7B Reactions of Acid Anhydrides :

(i) Conversion into acids. Hydrolysis :

Example :

(ii) Conversion into amides. Ammonolysis :

Example :

(iii) Conversion into esters :

(iv) Formation of Ketone : Friedel craft acylation

Amides

C8A Preparation : In the laboratory method of preparation of amide includes its preparation from acidchloride with ammonia, acid anhydride with ammonia.

In industry they are prepared by heating ammonium salts of carboxylic acids.

C8B Reaction of Amides :

1. Hydrolysis :

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2. Conversion into nitrile :

3. Conversion into imides :

Example :

4. Hoffmann degradation of amides :

Practice Problems :

1. The end product in the followin series of reaction is

)C()B()A(COOHCH 523 OPheatNH3

(a) CH4

(b) CH3OH

(c) acetonitrile (d) ammonium acetate

2. In a reaction, CNHC)C()B()A( 52OPheatNH 523 (A), (B) and (C) are :

(a) CH3COOH, CH

3COONH

4 and CH

3CONH

2

(b) CH3COCl, CH

3CONH

2 and CH

3COONH

4

(c) C2H

5COOH, C

2H

5COONH

4 and C

2H

5CONH

2

(d) C2H

5COONH

4, C

2H

5CONH

2 and C

2H

5COOH

[Answers : (1) c (2) c]

Esters :

C9A Preparation of Esters :

1. From acids :

Reactivity of OHR is 10 > 20 > 30

similarly > 10 > 20 > 30

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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 formintermolecular esterification occurs. Thus or hydroxy acid looses water spontaneously by yield ofcyclic ester known as lactone. Treatment with base (OH–) rapidly opens the lactone ring.

C9B Reactions of Esters :

1 Conversion into acids and acid derivatives

2. Conversion into amides

CH3COOC

2H

5 + NH

3 CH

3CONH

2 + C

2H

5OH

Treatment of an ester with ammonia, generally in ethylalcohol solution yield the amides. Thisreaction 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 H2SO

4 or dry HCl

Base alkoxide ion generally used.

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4. Reactions with Grignard Reagent :

5. Reduction to alcohols :

(a) Catalytic hydrogenation : Hydrogenolysis

OH'ROHRCHH2RRCOOalcohol1

2C250

OCuCr,CuO2

00

42

(b) Chemical Reduction : OHROHRCHLiAlHRCOOR 2ether.Anhyd

4

6. Reaction with carbanions : Clasien Condensation :

R

Example :

7. Crossed Clasien Condensation :

Like a crossed aldol condensation, a crossed clasien condensation is also possible only when one ofthe reactants has no -hydrogens and thus is incapable of undergoing self condensation.

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SINGLE CORRECT CHOICE TYPE

1. An organic compound gives hydrogen on reactingwith sodium metal. It also gives iodoform test andforms an aldehyde of molecular formula C

2H

4O on

oxidation with acidified dichromate. The compoundis :

(a) CH3OH (b) CH

3COOH

(c) CH3CHO (d) C

2H

5OH

2. In the following reaction, what is X, X 32SONa

Glycerol + acetaldehyde + CO2

(a) ethyl alcohol (b) glucose

(c) glycol (d) allyl alcohol

3. A compound with molecular formula C4H

10O

3 is

converted by the action of acetyl chloride to acompound with molecular weight 190. Theoriginal compound has

(a) one —OH group

(b) two —OH groups

(c) three —OH groups

(d) no —OH group

4. When acetaldehyde is treated with aluminiumethoxide, it forms

(a) ethyl acetate

(b) ethyl alcohol

(c) acetic acid

(d) methyl propionate

5. The compound is a condensation

product. It is obtained either by treating 3 moleculesof acetone with conc. H

2SO

4 or passing propyne

through a red hot tube. The polymer is

(a) phorone

(b) diacetonyl alcohol

(c) mesityl oxide

(d) mesitylene

6. The alkene which on ozonolysis yields only acetoneis

(a) CH2 = CH

2

(b) CH3 – CH = CH

2

(c) (CH3)

2C = C(CH

3)

2

(d) CH3CH = CHCH

3

7. Leaving tendency of the following in increasingorder :

(a) VI < V < III < II < IV < I

(b) I < II < III < VI < V < IV

(c) I < III < V < II < IV < VI

(d) can’t be decided

8. Formylchloride has not been prepared so far. Whichcan function as formylchloride in formylation

(a) HCHO + HCl

(b) HCOOCH3 + HCl

(c) CO + HCl

(d) HCONH2 + HCl

9. Formic acid is obtained when

(a) calcium acetate is heated with conc.H

2SO

4

(b) glycerol is heated with oxalic acid

(c) acetaldehyde is oxidised with K2Cr

2O

7

and H2SO

4

(d) calcium formate is heated with calciumacetate

10. The reaction,

2CCl

2 COAgBrRBrBrRCOOAg 4

is called

(a) HVZ reaction

(b) Hunsdieker reaction

(c) Hofmann’s reaction

(d) Carbylamine reaction

11. RCOOH + N3H .)conc(SOH 42 RNH

2 + CO

2 + N

2

The above reaction is called

(a) HVZ reaction

(b) Hunsdiecker reaction

(c) Schmidt reaction

(d) Decarboxylation reaction

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12. Which of the following reactions is expected toreadily give a hydrocarbon product in good yield

(a) isElectrolys

RCOOK

(b) 2BrRCOOAg

(c)hv

Cl33

2CHCH

(d) OHHC

3352ClC)CH(

13. Which of the following methods cannot be used forthe preparation of an ester

(a) RCOOH + ROH + H+

(b) RCOCl + ROH + Pyridine

(c) RCOOH + ROH + OH—

(d) (RCO)2O + ROH + Pyridine

14. When propionic acid is treated with aqueousNaHCO

3, CO

2 is liberated. The ‘C’ of CO

2 comes

from

(a) methyl group

(b) carboxylic acid group

(c) methylene group

(d) bicarbonate

15. Which will liberate ammonia when boiled withNaOH solution

(a) ethyl amine (b) acetamide

(c) aniline (d) all

16. Sodium acetate and acetyl chloride react to give

(a) acetic anhydride

(b) acetone

(c) acetic acid

(d) sodium formate

17. Acetyl chloride is not obtained from acetic acid bythe action of

(a) CHCl3

(b) SOCl2

(c) PCl3

(d) PCl5

18. Main product of the reaction CH3CONH

2 +

HNO2 is

(a) CH3NH

2(b) CH

3CH

2NH

2

(c) CH3COOH (d) CH

3OH

19. Urea is a

(a) monobasic acid (b) dibasic acid

(c) monoacid base (d) diacid base

20. Strongest acid out of

CH3CO

2H, CH

2 = CHCO

2H, —CO

2H

(a) CH3CO

2H

(b) CH2 = CHCO

2H

(c) —CO2H

(d) equal Ka

21. Explain the reactivity of acyl compounds in theorder

(a) acid chloride > amide > anhydride >ester

(b) acid chloride > anhydride > ester > amide

(c) ester > acid chloride > anhydride > amide

(d) ester > anhydride > acid chloride > amide

22. Which of the following acids is strongest

(a) C6H

5SO

3H (b) CH

3COOH

(c) C6H

5COOH (d) (COOH)

2

23. In the reaction,

)B()A(ClCHHC23 )NO(Cu

OxidationNaOH.Aq256 ,

(B) is

(a) benzoic acid (b) phenol

(c) toluene (d) benzaldehyde

24. In the following groups,

)IV(32

)III(2

)II()I(CFSO,MeOSO,OMe,OAc

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

25. Benzoic acid gives benzene on being heated with Xand 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

26. Salicylic acid on heating with soda lime forms

(a) benzene (b) phenol

(c) benzyl alcohol (d) benzoic acid

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27. Which aromatic acid among the following is weakerthan simple benzoic acid

(a) (b)

(c) (d)

28. When ethyl benzoate is hydrolysed with aqueousalkali, the products present in the medium are

(a) C6H

5COOH and C

2H

5OH

(b) C6H

5COOH and C

2H

5O—

(c) C6H

5COO— and C

2H

5OH

(d) C6H

5COO— and C

2H

5O—

29. In a cannizzaro’s reaction, the intermediate that willbe the best hydride donar is

(a)

(b)

(c)

(d)

30. C6H

10O

3 (A)

OH3 C4H

6O

3(B) + C

2H

6O(C) A,

B and C all gives iodoform test. A and B also formoximes, A is neutral but B gives CO

2 with NaHCO

3.

Hence A can be

(a) CH3COCH

2COOC

2H

5

(b) CH3CH

2COCH

2.COOCH

3

(c) CH3CH

2CH

2CO.COOCH

3

(d)

31. OHCH3 A A is :

(a)

(b)

(c) both are correct

(d) none is correct

32. The product (C) in the following reaction is

)C()B()A(RCOOHheat

OPheatNH 523

(a) RNH2

(b) RCN

(c) RNC (d) RCONH2

33. The reaction of with a mixture of

Br2 and KOH gives R — NH

2 as a product. The

intermediates involved in this reaction are

(a)

(b) R — N = C = O

(c) R — NHBr

(d)

34. Which of the following carboxylic acid undergodecarboxylation easily

(a) C6H

5COCH

2COOH

(b) C6H

5COCOOH

(c)

(d)

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35. OHCH3 A, A is :

(a)

(b)

(c) both are correct

(d) none is correct

36. BleadiponitriANi,H

PressureΔ,Δ

OH

acid)(Adipic

23

PolymerBA

The polymer is

(a) polyacrylonitrile

(b) nylon-6

(c) nylon 66

(d) butan-N

37. ‘A’ is an organic compound which can reduceTollen’s reagent, reduces mercuric chloride givinga black precipitate, decolourises acidified KMnO

4

and can reduce Fehling solution also. Compound‘A’ is

(a) HCOOH (b) CH = CH

(c) CH3CHO (d) CH

2 = CH

2

38. 3

2

FeBr

Br2 Product

The predominant product is

(a)

(b)

(c)

(d)

39. The product ‘G’ is

H

OHHC423

52COOH)CH(CH

4

2

56

KMnO

]O[.3OH.2

MgBrHC2.1

G

(a) acidic acid (b) valeric acid

(c) acrylic acid (d) butyric acid

ANSWERS (SINGLE CORRECTCHOICE TYPE)

11. c

12. a

13. c

14. d

15. b

16. a

17. a

18. c

19. c

20. c

1. d

2. b

3. b

4. a

5. d

6. c

7. a

8. c

9. b

10. b

31. a

32. b

33. b

34. a

35. a

36. c

37. a

38. c

39. b

21. b

22. a

23. d

24. b

25. d

26. b

27. c

28. c

29. c

30. a

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EXCERCISE BASED ON NEW PATTERN

COMPREHENSION TYPE

Comprehension-1

The mechanism of esterification of a carboxylic acidis as follows.

1. The slow step in the mechanism is

(a) Step 1 (b) Step 2

(c) Step 3 (d) Step 4

2. The overall order of the reaction is

(a) 1 (b) 2

(c) 3 (d) zero

3. The rate of esterification with the three differentalcohols CH

3OH, C

2H

5OH and CH

3CH

2CH

2OH will

follow the order

(a) CH3OH > C

2H

5OH > C

3H

7OH

(b) CH3OH < C

2H

5OH < C

3H

7OH

(c) CH3OH > C

3H

7OH > C

2H

5OH

(d) C2H

5OH > C

3H

7OH > CH

3OH

Comprehension-2

A mechanism for base-promoted hydrolysis of anester is as follows :

4. Which of the following steps is/are a slow step ?

(a) Step I (b) Step II

(c) Step III (d) Steps I and II

5. Which of the following steps is/are not a reversiblestep ?

(a) Step I

(b) Step II

(c) Step III

(d) All the three steps

6. If an ester from a chiral alcohol

, then the products of hydrolysis is

(a) with retention of

configuration of R’

(b) with inversion of


(c) with retention of


(d) with inversion of


MATRIX-MATCH TYPE

Matching-1

Column - A Column - B

(A) 3AlCl

(P)

(B) HCOHC

orSOH

356

52

(Q)

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(C)

.1

HCOHC.2

2

356Ca

(R)

(D)

(S)

Matching-2

Column - A Column - B

(A) Mandelic acid (P)

(B) Salicylic acid (Q)

(C) Succinic acid (R)

(D) Phthalic acid (S)HOOCCH

2CH

2COOH

MULTIPLE CORRECT CHOICE TYPE

1. Which is/are true

(a) H2NCH

2CH

2COOH

CH

2 = CH

COOH

(b) HOCH2 – CH

2 – CH

2 COOH

(c) HOCH2COOH

(d) H2NCH

2COOH H

3N+ – CH

2COO–

2. Which is/are wrong

(a) C6H

5COOH + (CH

3CO

2)O

(b) C6H

5COCl + (CH

3)

2Cd

C6H

5COCH

3

(c) C6H

5CONH

2 +

KOH C

6H

5CN

(d) C6H

5COOH 4LiAlH

C6H

5CHO

3. A positive carbylamine test is given by

(a) N, N-dimethylaniline

(b) 2, 4-dimethylaniline

(c) N-methyl-O-methyl aniline

(d) p-methyl benzylamine

4. Reaction of R CO NH2 with a mixture of Br

2 and

KOH gives RNH2 as the main product. The

intermediates involved in the reaction is/are

(a) R CO NH Br (b) R – NH Br

(c) R – N = C = O (d) R CO N Br2

5. Which of the following do not undergo basichydrolysis ?

(a) Esters (b) alkyl cyanides

(c) alkylisocyanides (d) Ethers

6. Alanine forms Zwitter ion which exists as

(a) in acidic medium

(b) (when PH = 4)

(c) (when PH = 13)

(d) (when PH = 2)

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Assertion-Reason Type

Each question contains STATEMENT-1 (Assertion)and STATEMENT-2 (Reason). Each question has4 choices (A), (B), (C) and (D) out of which ONLYONE is correct.

(A) Statement-1 is True, Statement-2 is True;Statement-2 is a correct explanationfor Statement-1

(B) Statement-1 is True, Statement-2 is True;Statement-2 is NOT a correctexplanation for Statement-1

(C) Statement-1 is True, Statement-2 is False

(D) Statement-1 is False, Statement-2 is True

1. STATEMENT-1 : m-amino benzoic acid reactswith Br

2 in HCl to form 2, 4, 6 tri bromo 3-amino

benzoic acid.

STATEMENT-2 : In above reaction – COOHgroup can be replaced by H by decarboxlylation.

2. STATEMENT-1 : CH3COOCH

3 > CH

3COOC

2H

5

> CH3COOCH(CH

3)

2 > CH

3COOC(CH)

3

There are in decreasing order on the case of thehydrolysis of esters.

STATEMENT-2 : More the steric hindranceeither on the alcoholic portion or on the acidportion of the ester, lesser will be the difficulty incarrying out hydrolysis.

3. STATEMENT-1 : The boiling and melting pointof carboxylic acids are higher than the alcohols.

STATEMENT-2 : The intermolecular forces areof greater for RCOOH.

4. STATEMENT-1 : P-NO2C

6H

4COOH is stronger

acid than pHCOOH.

STATEMENT-2 : The nitro acid does have a lesspositive H

rel, but the dominant factor is the

positive Srel

.

(Hrel

and Srel

are the relative values for theacids)

5. STATEMENT-1 : All ortho substituted acids arestronger than their para and meta counter parts.

STATEMENT-2 : The highly branched acids such

as are less acidic than

unbranched acids.

6. STATEMENT-1 : H-bromobutanoic acid whenreacted with aq. NaOH, it forms H-butanolide.

STATEMENT-2 : It is 2NS type reaction.

7. STATEMENT-1 : R – C N is hydrolysed to formRCOOH.

STATEMENT-2 : Nitrogen atom is empelled asammonium ion in above reaction.

8. STATEMENT-1 : In , more basic

oxygen is O denoted by x.

STATEMENT-2 : In . The bond

length between z and x is larger as compare tobetween z and y.

9. STATEMENT-1 : Decarboxylation will not takeplace on heating of succinic acid.

STATEMENT-2 : Carboxylic acid undergoesionisation due to resonance stabilisation ofcarboxylate ion.

10. STATEMENT-1 : In a Claisen Condensationreaction carbanion act as a nucleophile in anucleophilic actyl substitution reaction withanother ester molecule.

STATEMENT-2 : In a Claisen Condensationreaction enolate carbanion is resonance stabilised.

(Answers) EXCERCISE BASED ON NEW PATTERN

COMPREHENSION TYPE

1. b 2. c 3. a 4. a 5. c 6. a

MATRIX-MATCH TYPE

1. [A-Q ; B-S ; C-P ; D-R] 2. [A-P ; B-R ; C-S ; D-Q]

MULTIPLE CORRECT CHOICE TYPE

1. a, b, c, d 2. c, d 3. b, d 4. a, c 5. c, d 6. b, c

ASSERTION-REASON TYPE

1. B 2. C 3. A 4. A 5. B 6. A

7. A 8. D 9. B 10. C

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INITIAL STEP EXERCISE

(SUBJECTIVE)

1. Account for the following :

(a) Acetic acid can be halogenated inpresence of phosphorus and chlorine butformic acid cannot be halogenated in thesame way.

(b) Carbon-oxygen bond lengths in formicacid are 1.23 Å and 1.36 Å but in sodiumformate both carbon-oxygen bonds havesame value, i.e. 1.27 Å.

(c) -Keto acids undergo decarboxylationeasily.

2. A liquid (X) having molecular formula C6H

12O

2 is

hydrolysed by water in presence of an acid to givea carboxylic acid (Y) and an alcoholic (Z).Oxidation of (Z) with chromic acid gives (Y). Whatare (X), (Y) and (Z) ?

3. An alkene (A) on ozonolysis yields acetone and analdehyde. The aldehyde is easily oxidised to an acid(B). When (B) is treated with phosphorus andbromine, it yields a compound (C) which onhydrolysis gives a hydroxy acid (D). This can alsobe obtained from acetone by reaction with HCNfollowed by hydrolysis. Identify (A) to (D).

4. Compound (A) C5H

8O

2 liberated carbon dioxide on

reaction with sodium bicarbonate. It exists in twoforms neither of which is optically active. It yieldscompound (B) C

5H

10O

2 on hydrogenation.

Compound (B) can be separated into twoenantiomorphs. Write the structural formulae of(A) and (B) giving reason.

5. What happens when :

Acetamide is heated with bromine and causticpotash.

6. Identify A, B, C, ... in the following equations :

(i) )B()A(CHCH42

4

]O[SOH

HgSO

)D()C()3

2

AlCl

BenzeneSOCl

(ii)

COOHCH)A(O)COCH( 3OHHC

2355

(iii) )B()A(BrHCSOH

OCrNaKOH52

42

722

)C() Al)OHC( 352

7. Convert n–C5H

11CO

2H into n–C

4H

9CO

2H by three

methods.

8. Which of the following would be most and leastreadily hydrolysed with NaOH, and why ?

(i) MeCO2Me;

(ii) Me2CHCO

2Me;

(iii) MeCO2But

9. Complete the equations and comment :

(i) ?COClCHClLAH

2

(ii) ?CNCHHOCHOHHBr

222

(iii) ?NaIHCOClCHacetone

22

(iv) ?CBrCONHMe2Br

NaOH22

10. Identify the principal organic product :

Aheat

11. Outline synthesis of benzyl benzoate using toluene.

2

||O

OCHC

12. Show the following conversions in minimum stepspossible.

(a) Acetic acid to crotonic acid

(b) Benzaldehyde to cyanobenzene

13. Compound (A) with molecular mass 108 contained88.89% C and 11.11% H. It gave a whiteprecipitate with ammonical silver nitrate. Completehydrogenation of (A) gave another compound (B)with molecular mass 112. Oxidation of (B) withmolecular mass 112. Oxidation of (B) gave an acidof equivalent mass 128. Decarboxylation of this acidgave cyclohexane. Give structures of (A) and (B)and write the equations of the reactions involved.

14. Complete the following reaction :

OH/H.2

OCH.1

2

3

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15. Complete the following with appropriatestructures :

(i)

?COOHCHO)COCH( 3OHHC

2352

(ii)

?base

16. A liquid (X) having a molecular formula C6H

12O

2 is

hydrolysed with water in the presence of an acid togive a carboxylic acid (Y) and an alcohol (Z)oxidation of (Z) with chromic acid gives (Y). Whatare the structures of (X), (Y) and (Z)

FINAL STEP EXERCISE

(SUBJECTIVE)

1. An organic compound (A) on treatment withacetic acid in presence of conc. sulphuric acidproduces an ester (B). (A) on mild oxidation gives(C). (C) with 50% KOH followed by acidificationwith dilute HCl generates (A) and (D). (D) with PCl

5

followed by reaction with ammonia gives (E). (E)on dehydration produces HCN. Identify thecompounds (A), (B), (C), (D) and (E).

2. An organic compound (A) on treatment with ethylalcohol gives a carboxylic acid (B) and a compound(C). (C) on hydrolysis under acidic conditions gives(B) and (D). Oxidation of (D) with KMnO

4 also gives

(B). (B) on heating with Ca(OH)2 gives (E).

Molecular formula of (E) is C3H

6O. (E) does not

give Tollen’s test and does not reduce Fehling’ssolution but forms 2, 4-dinitrophenyl hydrazone.Identify (A) to (E).

3. An organic acid (A), C5H

10O

2 reacts with Br

2 in the

presence of phosphorus to give (B). Compound (B)contains an asymmetric carbon atom and yields (C)on dehydrobromination. Compound (C) does notshow geometric isomerism and on decarboxylationgives an alkene (D) which on ozonolysis gives (E)and (F). Compound (E) gives a positive Schiff’s testbut (F) does not. Give structures of (A) to (F) withreasons.

4. An acidic compound (A), C4H

8O

3 loses its optical

activity on strong heating yielding (B), C4H

6O

2

which reacts readily with KMnO4. (B) forms a

derivatives (C) with SOCl2, which on reaction with

(CH3)

2NH gives (D). The compound (A) on

oxidation with dilute chromic acid gives an unstablecompound (E) which decarboxylates readily to give(F), C

3H

6O.

5. Identify A, B, C,....in the following equations :

(i)

)C()B()A( 23 MeNHPClMeOH

(ii)

6. Compound (A) (C6H

12O

2) on reduction with LiAlH

4

yielded two compounds (B) and (C). The compound(B) on oxidation gave (D) which on treatment withaqueous alkali and subsequent heating furnished(E). The latter on catalytic hydrogenation gave (C).The compound (D) was oxidised further to give (F)which was found to be monobasic acid (molecularmass = 60.0). Deduce the structure of (A), (B), (C),(D) and (E).

7. Two moles of an ester (A) are condensed in the pres-

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ence of sodium ethoxide to give a -keto ester (B)and ethanol. On heating in an acidic solution (B)gives ethanol and -keto acid (C). On decar-boxylation (C) gives 3-pentanone. Identify (A), (B)and (C) with proper reasoning. Name the re-action involved in the conversion of (A) to (B).

8. Convert : (i) n-BuOH into n-PrNH2;

(ii) Et2CHCO

2H

into Et2CHCHO

9. An aromatic compound (A) C8H

9Br reacts with H

2C

(COOC2H

5)

2 in the presence of C

2H

5ONa to give (B).

Compound (B) on refluxing with dilute H2SO

4 gives

(C) which on vigorous oxidation gives (D). Thecompound (D) is dibasic acid but on heating doesnot give an anhydride. It forms a mononitroderivative (E), in which all the substituents are atequidistant from one another. Give structure of (A)to (E) with proper reasoning.

10. Give the structure of the principal organic productof following reaction

(a)

422 SOH,OH

(b) What reagent are needed to carry outeach of the following conversions ?

(i) C6H

5CH

2CO

2H ?

ClCCHHC||O

256

(ii) (CH3)

2CHCH

2NH

2 ?

OHCH)CH(CHNHCHCHC 3232

||O

56

11. An organic acid (A) on heating with AlPO4 at 7000C

forms (B). Compound (B) also reacts with (A) togive (C). Compound (C) on reaction with 1, 3,5-trimethyl benzene in presence of AlCl

3 gives a

ketone (D) and CH3COOH. (D) on treatment with

Na (Hg)/HCl gives an aromatic hydrocarbon (E).Give structures of (A) to (E) with properreasoning.

12. An aromatic ketone X has the molecular formulaC

10H

12O

2. On vigrous oxidation, it gives Y, a diba-

sic acid (C9H

8O

5) which easily gives anhydride on

heating. The ketone X gives Z (C9H

10O

3) a

mono-basic acid with Br2 and NaOH. Z on

decarboxylation with sodalime gives3-methylanisole. Determine the structures of X, Yand Z and gives involve dreactions.

13. 1, 4-pentadiene reacts with excess of HCl in thepresence of benzoyl peroxide to give compound Xwhich upon reaction with excess of Mg in dry etherforms Y. Compound Y on treatment with ethylacetate followed by dilute acid yields Z. Identify thestructures of compounds X, Y and Z.

14. A mixture of calcium benzoate and calcium formateon dry distillation produces compound A. Com-pound A on reaction with hot NaOH solution pro-duces two compound C and D. Compound C ontreatment with HCl leads to E which undergoesreduction with LiAlH

4 to give D. Reaction of E with

EtOH and conc. H2SO

4 produces F which reacts

with excess of CH3MgI and forms G. Treatment of

G with sulphuric acid produces H with loss of H2O.

Ozonolysis of H leads to I & J. I on reaction with I2

and alkali followed by acidification produces Ealong with iodoform. What are the lettered com-pound A to J ?

15. Show the following transformation not more thanfour steps. –Hydroxybutyric acid 4-Methyl-1,4-pentanediol

16. 0.15 g of an ester (A) of vapour density = 30 gave0.22 g CO

2 and 0.09 g H

2O. (A) on treatment with

alkali hydrolysis gives alcohol (B) and an organiccompound (C). (B) can also be obtained byreduction of (A). (C) reduces Tollen’s reagent. Whatare (A), (B) and (C) ?

17. Esters and amides can be hydrolyzed under acidicor basic conditions. Rank the following compoundsin order of decreasing reactivity towards aqueoushydroxide anion.

CH3CO

2CH

3, CH

3CO

2CH

2CH

3, CH

3CO

2CH

2 –

, CH3CO

2C(CH

3)

3

18. Apigenin is a widely used distributed flavonoid. Itsstructure is shown below :

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In the following reactions draw the structures ofproducts B and C.

CApigenin

BApigenin

Pyridine

)excess(anhydrideacetic

MeIexcess.2Na.1

19.

Identify the structure of cantharidin and com-pounds from (i) to (n).

20. Complete the following transformations :

(i)

C180

SOH.conc

HN

H)ii(

NaOBr)i(

AlCl

AcCl0

42

3

3

DCBA

(ii)

21. Each of the following reactions gives a single prod-uct in good yield. What is the product in each reac-tion ?

(a) 42SOH,ethanol

(b)

OH.3

CO.2

etherdiethyl,Mg.1

3

2

(c) —CO2H

OH.2

LiAlD.1

2

4

(d) H2C = CH(CH

2)

8CO

2H

HBr

peroxidebenzoyl

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CARBOXYLIC ACIDS AND DERIVATIVES - Einstein …einsteinclasses.com/Carboxylic Acids_Ac_De.pdf · CCAD – 3 Einstein Classes, Unit No. 102, 103, Vardhman Ring Road Plaza, Vikas Puri