Isomerism Organic Halide - Dr. Sangeeta Khanna€¦ · 02.08.2017 · Dr. Sangeeta Khanna Ph.D 1 CHEMISTRY COACHING CIRCLE D:\Important Data\2017\+2\Organic\Grand Test\+2 Grand Test-V.doc

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Dr. Sangeeta Khanna Ph.D 1 CHEMISTRY COACHING CIRCLE D:\Important Data\2017\+2\Organic\Grand Test\+2 Grand Test-V.doc

Isomerism

Organic Halide

Dr. Sangeeta Khanna Ph.D


Test Date: 12.8.2017 Topic: Organic Halide & Isomerism

READ INSTRUCTIONS CAREFULLY 1. The test is of 2 hour duration. 2. The maximum marks are 380. 3. This test consists of 87 questions. 4. Keep your mobiles switched off during Test in the Halls.

(Single Correct Choice Type) Negative Marking [-1]

This Section contains 45 multiple choice questions. Each question has four choices A), B), C) and D) out

of which ONLY ONE is correct. Marks: 45 × 4 = 180

1. In the given reaction PhMgBr + D2O (X); (X) will be:

a. b. c. d.

D

Sol.

2. When the concentration of alkyl halide is triple and concentration of HOΘ

is reduced to half, the rate of

SN2

a. 3 times b. 1.5 times c. 2 times d. 6 times

B

Sol. Rate = K[Halide] [OH–]

3.

Compound A is:

a. b. c. d.

A Sol. [Diazotisation & sandmeyer] 4. Order of stability of alkene is

)X(23 CHCHCH

)Y(

2

3

3

CHCCH

CH

\/

)Z(

2

3

3

|

|3 CHCH

CH

CH

CCH is:

a. X > Y > Z b. Y > X > Z c. Z > X > Y d. Y > Z > X B

Sol. [Stability Hyperconjugation]

OH OD D

MgBr D DOD

Br

Br

NH2 NH2

Br

N2Br

NH2 1. NaNO2 + HCl

2. HBr, CuBr A



5. Geometrical isomerism is possible in :

a. b. c. d. D

6. a. Diastereomers b. Enantiomers c. Tautomers d. Conformers A 7. Which of the following is used as a purity test for chloroform?

a. aq. KOH b. aq. KOH + AgNO3 c. AgNO3 solution d. Oxidation test C

8. t-butyl bromide temp. low

KOH .aq (X). The main product (X) is

a. tertiary butyl alcohol b. 1-butoxy butane c. iso-butylene d. propene A

9. When ethyl benzene is treated with one equivalent N-bromosuccinimide in CCl4, the major product obtained is

a. b. c. d. B Sol. Benzylic Bromination with NBS 10. The decreasing reactivity order of halides towards dehydrohalogenation is

a. RI > RCl > RBr > RF b. RI > RBr > RCl > RF c. RF > RCl > RBr > RI d. RF > RI > RBr > RCl B

11. C6H5 – CH3 + Cl2 K 800

C6H5CH2Cl + HCl. This reaction takes place mainly by

a. SN1 mechanism b. SN2 mechanism c. free radical mechanism d. E1 mechanism C

12. (A) 3 AgNO)ii(

NaOH aq.)i( white precipitate.

(A) can be a. vinyl chloride b. benzyl chloride c. chlorobenzene d. o-chlorotoluene B

OH

OH

H

OH

H

H

HO

H

H

O

CH2OH

and

OH

H

OH

H

H

HO

H

H

O

CH2OH

HO

are:

CH2CH2Br CH(Br)CH3 CH2CH3

Br

CH2CH3

Br



13. In an SN1 reaction on chiral centres, there is:

a. inversion more than retention leading to partial racemization b. 100% retention c. 100% inversion d. 100% racemization A

Sol. SN1 reaction gives racemic mixture with slight predominance of that isomer which corresponds to inversion because SN1 also depends upon the degree of 'shielding' of the front side of the reacting carbon.

14. is (B) product The )B()A(ICHCHH

CH

CClH/OH

mole 1

CN22

|

2Θ

3

a. HOOC – CH2 – CH2 – I b. COOHCHCHH

CH

CHOOC 22|

3

c. COOHCHCHH

CH

CCl 22|

3

d. ICHCHH

CH

CHOOC 22|

3

C Sol. Iodide is more reactive & -CN gp on complete hydrolysis give acid. 15. What will be the order of reactivity for the nucleophilic substitution of chlorine in the following compounds? a. (A) > (C) > (B) > (D) b. (D) > (B) > (A) > (C) c. (C) > (A) > (B) > (D) d. (D) > (B) > (C) > (A) B Sol. [e– withdrawing gp increases Reactivity]

16. Which of the following alcohols will give a yellow coloured precipitate with iodine and sodium hydroxide?

a. b. c. d. D 17. The correct order of SN2 reactivity among the following is

a. CH3Cl > CH3Br > CH3I b. CH3Br > CH3CH2Br > (CH3)2CHBr c. CH3CH2Cl > CH3CH2CH2Cl > CH3Cl d. (CH3)3CBr > (CH3)2CHBr > CH3CH2CH2Br B

Cl

NO2

Cl

NO2

Cl

OH

Cl

CHO

NO2

(A) (B) (C) (D)

CH2 C CH

CH3

CH3

CH3

OH CH2 CH2 CH2 C CH3

CH3

OH

OH

CH3

CH2 CH CH3

OH CH3



18. Which of the following is the correct order of dipole moment of methyl halides?

a. CH3F > CH3Cl > CH3Br > CH3I b. CH3Cl > CH3F > CH3Br > CH3I c. CH3I > CH3Br > CH3F > CH3Cl d. CH3I > CH3Br > CH3Cl > CH3F B

19. 2-Bromopentane 3 3 3 3(CH ) COK /(CH ) COH

P

The major product (P) formed in the above reaction is a. pent-1-ene b. cis pent-2-ene

c. trans pent-2-ene d. 33|

223 )CH(OCH

CH

CCHCHCH

3

A Sol. Hoffmann’s product with Bulky base. 20. Chloroform on boiling with NaOH solution gives

a. sodium methoxide b. Methanal c. sodium methanoate d. dichloromethanol C

Sol. 3KOH KOH3CHCl HCOOH HCOOK

21. The organic compound formed in the following reaction is

C6H5COOAg + Br2 ref lux/CCl4 product

a. C6H5COOBr b. C6H5Br c. d.

B

22. The product formed when isopropyl alcohol is heated with a Cl2 + NaOH(aq.) is

a. propyne b. 2-chloropropane c. chloroform d. carbon tetrachloride C

23. The correct order of reactivity of the following alcohols with hydrobromic acid (HBr) is

)I(

ol1anphenylprop1 )II(

ol2anphenylprop1 )III(

ol1anphenylprop3

a. I > II > III b. I > III > II c. III > I > II d. III > II > I A

Sol. Order of Reactivity Pri. < Sec. < tert. 24. Which of the following statements is correct?

a. CH3CH2S– is a stronger base, but weaker nucleophile than CH3CH2O

–. b. CH3CH2S

– is a weak base, but more nucleophilic than CH3CH2O–.

c. CH3CH2S– is a stronger base and more nucleophile than CH3CH2O

–. d. CH3CH2S

– is a weak base and less nucleophilic than CH3CH2O–.

B 25. Identify the false statement among the following

a. The rate of hydrolysis of tert-butyl chloride does not change by increasing the concentration of OH–

[SN1]

b. 2-phenylethanol reacts with thionyl chloride to give a chloro compound with almost complete retention of configuration [SNi]

c. Polar solvents generally increase the rate of SN1 reactions. d. SN2 reaction of optically active substrate leads to racemization if the leaving group is attached to

the chiral carbon. D

COOBr

Br

COOH

Br



26. The configuration of the product in the following reaction a. b. c. d. None B 27. What is the relationship between the pair of compounds shown? a. Identical: superimposable without bond rotations b. Conformations

c. Stereoisomers d. Constitutional isomers C

28. Correct IUPAC name of following compound is

a. 2-Chlorocyclohexene b. 3-Chlorocyclohexene c. Cyclohexenylchloride d. 1-Chlorocyclohex-2-ene B

29. is X ;X2Cl Fe

a. b. c. d. None

B Sol. CCl3 group is meta directing. 30. Which of the following reaction(s) can be used for the preparation of alkyl halides ?

(I) 2anh. ZnCl3 2CH CH OH HCl

(II) CH3CH2OH + HCl

(III) (CH3)3COH + HCl (IV) 2anh. ZnCl3 2(CH ) CHOH HCl

a. (I) and (II) only b. (IV) only c. (III) and (IV) only d. (I), (III) and (IV) only D Sol. (I) and (IV) can be used due to presence of anhydrous ZnCl2 (III) gives alkyl halide due to formation of

more stable carbocation.

D

Br H

CH2 – CH3

NaI/acetone Product

D

H

CH2 – CH3

I

D

H

CH2 – CH3

I

CH2 – CH3

D

I H

H

H3C

H H

H3C

H

Cl

CCl3

Cl

CCl3

Cl

CCl3

Cl

CCl3



31. Which of the following statements is not correct for a nucleophile ?

a. Ammonia is a nucleophile b. Nucleophiles attack low e– density sites

c. Nucleophiles are not electron seeking d. Nucleophile is a Lewis acid

D

Sol. Reason: Nucleophiles are electron rich species so act as Lewis base.

32. The number of structural isomers possible from the molecular formula C3H9N is :

a. 5 b. 2 c. 3 d. 4

D

Sol.

33. In the reaction with HCl, an alkene reacts in accordance with the Markovnikov's rule, to give a product

1-chloro-1-methylcyclohexane. The possible alkene is

a. b. c. d.

A,D

Sol. 34. a. b. c. d. No reaction D Sol. H and Br are not anti position.

CH2 CH3 CH3 CH = CH2

CH2

H+

CH3

Cl–

Cl

CH3 CH3

Cl–

Cl

CH3 or

CH3

Br

CH3ONa Product:

CH3



35. Which Bromine is most reactive for SN2 attack of CH3O

– ion a. I b. II c. III d. IV A

Sol. [electron withdrawing group increases Reactivity in SN2]

36. a. b. c. d.

B

37. 2 4

3

Cl (1 mol) NBS / CCl6 5 3

FeClC H CH (A) (B)

The structure of (c) is

a. b. c. d.

A

Sol.

Br

Br

Br

Br

O

(I)

(IV)

(II)

(III)

Br

Br

Br

Br

O

(I)

(IV)

(II)

(III)

HO CH = CH – CH3 HBr Major product:

CH2 – CH – CH3

Br

HO

Br

CH – CH2 – CH3 HO

CH = CH – CH2 – Br HO CH2 – CH2 – CH2 – Br HO

CH2CH2CH2OH

Cl

CH2CH2CH2OH

CH3

Cl

CH CH2

O

Cl

CH2CH2OH

(i) Mg/ether

(ii)

O

(iii) H3O+

(C)

CH3

Cl

NBS

CH2Br

Cl

Mg

CH2MgBr

O

CH2 – CH2 – CH2

OH

Cl

(i)

(ii) HOH Cl



38. To prepare 2-Methylbutane from ethyl chloride which of following will be the best reagent?

a.

3

3|

CH CH Cl Na (dryether)

CH

b.

3

3|

CH CH Li CuX

CH

c. CH3CH2CH2 – Li + CuX d.

3| Na

3 2

CH

CH C CH Cl (dryether)H

B Sol. 39. Which of the following alkyl bromides may be used for the synthesis of 2, 3-dimethyl butane by Wurtz

reaction?

a. b. c. Isobutyl bromide d. s-butyl bromide B

Sol. 40. Which among the following pairs are diastereomers:

1. 2. 3. 4. Select the correct answer from the codes given below : a. only 2 b. only 1 c. 1 and 2 d. 1, 2 and 4 D 41. Which of the following compounds are meso forms?

a. 1 only b. 3 only c. 1 and 2 d. 2 and 3

B

CH3 CH Cu LI

CH3

+ CH3CH2 Cl

2CH3 CH Li

CH3

CH3 CH CH2 CH3

CH3

2-Methylbutane

CuX

2

Br

Br

Br + 2Na + Br dry ether

CH3

H

C C

H

CH3

and

CH3

H

C C

H

CH3

COOH

CH2OH

C

C H

H

OH

OH

COOH

CH2OH

C

C H

H

HO

OH

and

CH2OH

C OH

CHO

H and

CH2OH

C

CHO

H HO

Br

C

C C

F

I

Br

C

C C

F

I and

OH H

C2H5

H OH

CH3

1

H

H

CH3

2

Cl

Cl

CH3

CH3

CH3

3



42. Consider the following pair of compounds: Which among the following statements is correct?

1. Both are enantiomers 2. Both are in threo form 3. Both are diastereomers 4. Both are in erythro form

a. 1 and 2 b. 1, 2 and 3 c. 2 and 3 d. 3 and 4 A

43. Consider the following reaction sequence In this B and D respectively are a. b. c. d. A 44. A hydrocarbon ‘A’ with molecular mass 84 gives a single monochloride but four dichlorides (only

structural) on photochemical chlorination. The hydrocarbon ‘A’ is

a. Cyclopentane b. Cyclohexane c. 2, 3-Dimethylbutane d. Methyl cyclopentane B

Sol.

Single monochloro product

Four dichloro products 45. Match the column – I with column – II

Column I Column II

(A) Chlorobenzene3NH liq. in

2NaNH (p) meso-2, 3-Dibromobutane

(B) cis-2-Butene 2Br (q) Benzyne mechanism

(C) trans-2-Butene 2Br (r) Bimolecular mechanism

(D) p-Nitrochlorobenzene

KOH .Aq (s) (±)-2, 3-Dibromobutane

OH H

C2H5

H

CHO

(1)

HO OH H

C2H5

H

CHO

(2)

HO

Cl

NO2

and

Cl

NO2

Cl

SO3H

and

Cl

NO2

Cl

NO2

and

NO2

Cl NO2

Cl

NO2

and NO2

Cl

Cl2/FeCl3

HNO3/H2SO4

A HNO3/H2SO4

B

C Cl2/FeCl3

D Below 330K

Cl

Cl2. h Cl2. h C6H12 (mol. wt. 84)

(A)

Cl Cl

+

Cl

Cl +

Cl

Cl

+

Cl

Cl



a. A – p ; B – r; C – q ; D - s b. A – q ; B – s ; C – p ; D – r c. A – p ; B – r; C – s ; D – q d. A – q ; B – r, C – s ; D – p B Sol. A(chlorobenzene) – q(benzyne mechanism); B(cis-2-butene)-s ((±)-2, 3-dibromobutane); C(trans-2-butene)-p(meso-2, 3-dibromobutane); D(p-nitrochlorobenzene)-r-(bimolecular /mechanism). ArSN2

SECTION – B (ASSERTION & REASON) Negative Marking [-1] This Section contains 10 multiple choice questions. Each question has four choices A), B), C) and

D) out of which ONLY ONE is correct. (10 × 4 = 40 Marks)

(a) Statement -1 is True, Statement-2 is True; Statement-2 is a correct explanation for Statement-1

(b) Statement- 1 is True, Statement-2 is True; Statement-2 is NOT a correct explanation for Statement-1 (c) Statement-1 is True, Statement -2 is False (d) Statement – 1 is False, Statement-2 is True 1. Statement – 1: Nucleophilicity does not always match with basicity.

Statement – 2: While nucleophilcity is more related to size, polarizability and steric factors, the basicity is the ability to abstract a proton from a substrate & depend on stability of bond with hydrogen a. (a) b. (b) c. (c) d. (d) A

2. Statement– 1: CH3 – CH2 – CH2Br when treated with NaCN gives mainly the corresponding cyanide or nitrile. Statement – 2: Sodium cyanide have only one nucleophilic centre on carbon atom. a. (a) b. (b) c. (c) d. (d) C

Sol. C N is ambident Nucleophile.

3. Statement – 1: Fluorobenzene undergoes nucleophilic substitution much faster than chlorobenzene. Statement – 2: Fluorine being more electronegative causes more decrease in electron density at the carbon leading to a faster attack by the nucleophile & it also stablise intermediate formed after nucleophilic attack. a. (a) b. (b) c. (c) d. (d) A

4. Statement – 1: In Reimer Tiemann reaction of phenol only one aldehyde group will be introduced at either ortho & para position Statement – 2: Aldehyde group introduced after first RTR, will deactivate the ring for further Reimer

Tiemann’s reaction

a. (a) b. (b) c. (c) d. (d)

A

5. Statement – 1: Order of acidic strength of trihalomethane is:

CHCl3 > CHF3 > CHBr3 > CHI3

Statement – 2: Conjugate base of CHCl3 is resonance stabilized for, rest of the trihalide decrease in –I

effect will decrease the acidic strength.

a. (a) b. (b) c. (c) d. (d)

A



6. Statement – 1: Aliphatic pri-amine are less reactive than aromatic pri.amine on reaction with CHCl3 &

alc. KOH

Statement – 2: Both give foul smelling isocyanide on reacting with CHCl3 & alc. KOH

a. (a) b. (b) c. (c) d. (d)

D

7. Statement – 1:

OH CHNCHCHPh

32

322

CHCH

CH CH CH

|

|322 on heating in presence of Ag2O give

vinylbenzene as major product

Statement – 2: Least acidic -hydrogen will be attacked by OH–. a. (a) b. (b) c. (c) d. (d) C

8. Assertion. CHBr = CHCl exhibits geometrical isomerism but CH2Br – CH2Cl does not. Reason. Geometrical isomerism arises due to restricted rotation about C = C double bond a. (A) b (B) c. (C) d. (D) A 9. Assertion. Twist boat conformation of cyclohexane is more stable than boat formation. Reason. Flagpole-flagpole interactions are less severe in boat conformation than in twist boat

conformation.

a. (A) b.(B) c. (C) d. (D)

C

10. Assertion. Stereoisomers which are not mirror images are called diastereomers.

Reason. Diastereomers may or may not be optically active.

a. (A) b. (B) c. (C) d. (D)

B

SECTION – C (Paragraph Type) Negative Marking [-1]

This Section contains 2 paragraph. Each of these questions has four choices A), B), C) and D) out of which ONLY ONE is correct. 9 × 4 = 36 Marks

Comprehension – 1 Since Grignard reagents resemble carbanion so they are strong nucleophile and strong base. Their most useful nucleophilic reaction is addition to carbonyl group.

X

OH

MgOHCRgXMOCROC gXMR/

\

|

|

HOHΘ|

|

Θ \

/

1. Which of the following compounds will not give acid-base reaction with RMgX?

a. CH3 – CH2 – Cl b. CH3OH c. NH3 d. H2S A

Sol. CH3CH2 – Cl give substitution reaction.



2. Which of the following compounds give racemic mixture on reaction with H3C – MgBr?

a. H

O

CH| |

b. 3

| |

3 CH

O

CCH c. H

O

CPh| |

d. Cl

O

CCH| |

3

C

Sol. gBrMHC OCPh

H3

Θ\/

Racemic Product

3. What will be the final product in the following:

a. COOHCHH

CH

CCH 2|

3

3

b. COOHCHCHH

CH

CCH 22|

3

3

c. 3|

3 CHH

CNCH

CCH

2

d. CH3CH2CH2CH2COOH

B Sol. 4. Which of the following will give sec. alcohol with excess of grignard Reagent

a. 3||

3 CH

O

CCH b. HCOOC2H5 c. CH3COCl d. HCHO

B

Sol.

alcohol .sec

|

|HOH

RMgX||

|52

||

OH

R

R

CH

O

R

CHMgX -R HOC

O

CH

5. Which of the following is the final product of given reaction. a. b. c. d. D

CH3 – CH – Cl

CH3

(1) Mg dry

ether A

(2) O

(3) HOH (4) PCl5

B (5) KCN

(6) HOH D

CH3 – CH – CH3

Cl

Mg CH3 – CH – CH3

MgCl

O

HOH CH3 – CH – CH3

CH2CH2OH

(1) PCl5 (2) KCN

CH3 – CH – CH2 – CH2CN

CH3

HOH CH3 – CH – CH2 – CH2COOH

CH3

O

1. C2H5MgBr

2. HOH Product

CH2

OH

C2H5 H3C – C – C2H5

OH

CH3

CH3 – C – CH2 – CH2 – CH3

OH

CH3



Sol.

Passage – 2

Under common reaction conditions, a carbocation rearranges to another carbocation of equal or

greater stability. For example, secondary carbocation will rearrange to a tertiary carbocation. It will not

rearrange to a less stable primary carbocation. This generalization is not absolute, and because there

is not a high energy barrier to the rearrangement of carbocations, rearrangement to a less stable cation

can occur if it offers the chance to form a more stable product.

6. In which of the following cations rearrangement takes place?

a. b. c. d.

D

Sol.

7. In which of the following cations rearrangement takes place most rapidly?

a. b. c. d.

A

Sol.

8. In the following cation, H/CH3 that is most likely to migrate to the positively charged carbon is:

35

3

|

|

4

|

3|

|

213 CH

H

CH

C

H

C

H

OH

CCH

a. CH3 at C – 4 b. H at C – 4 c. CH3 at C – 2 d. H at C – 2 D Sol.

9. 2,3-Dimethyl-2-butene can be prepared by heating which of the following compounds with a strong acid ?

a. (CH3)3C – CH = CH2 b. (CH3)2C = CH – CH2 – CH3

c. (CH3)2CH CH2 CH = CH2 d.

3

3 2 2|

(CH ) CH CH CH CH

CH

CH2 CH2

C – CH2

H

CH3

CH3 – C – CH2

H

CH3

CH2

CH2

C – CH2

H

CH3

Ph – C – CH2

CH3

CH3 C CH C CH3

CH3

H H

OH

CH3 C CH2 CH

OH

CH3

CH3

O

1. C2H5MgBr

2. HOH

C2H5

OH



A

Sol.

SECTION – D (More than One Answer Type) No Negative Marking

This Section contains 10 multiple choice questions. Each question has four choices A), B), C) and

D) out of which One or More than one answer may be correct. 10 × 5 = 50 Marks

1. Which of the following are correct order of nucleophilicity?

a. 223 HNHNHN

b. Θ||

3

ΘΘ

23 O

O

CCHHOOCHCH

c. ΘΘΘΘ IBrClF d.

A,B,D 2. Which of the following are electrophiles?

a. BF3 b. 2CCl c. 4HN

d. ΘI

A,B

Sol. H

H

H

NH|

| Complete octet, not electrophilic.

3. Which of the following have asymmetric carbon atom? a. CH2Cl-CH2Br b. CH3-CHCl2 c. CH3-CHDCl d. CH2Br-CHOH-CH3 C, D

4. Which structure/s has (R) configuration ?

a. b. c. d. A,C 5. Which of the following will not give addition reaction with RMgX?

a. CO2 b. CH3 – CH2 – Br c. SO2 d. OH

O

CCH| |

3

B,D Sol. (b,d) (b) gives substitution reaction while (d) gives acid base reaction.

O > H3C – C H3CO O

O

H HO

CH2CH3

CH3

H

CH3 Et

Br

H

Cl

C2H5

C3H7

H

COOH HO

CH3

H+

-H+

H3C C CH = CH2 H3C C CH CH3

CH3

CH3

CH3

CH3

CH3 – shift H3C C CH CH3

CH3 CH3

H3C C = C CH3

CH3 CH3



6. For an SN2 reaction, which of the following statements are true?

a. The rate of reaction is independent of the concentration of the nucleophile. b. The nucleophile attacks the C-atom on the side of the molecule opposite to the group being

displaced c. The reaction proceeds with simultaneous bond formation and rupture. d. More than one transition states are formed B,C

7. Which of the following are chiral?

a. O

CH

HC

PHC

3

56

|

|52 b. OS

CH

Ph

\/

3

c. H

CH

HC

NHC

3

56

|

|52 d. OS

CH

CH

\/

3

3

A, B, C 8. Which of the following is the correct order as indicated

a. FH

CH

CCH

3

|3 < CH3 – CH2 – CH2Cl < CH3 – CH2 – CH2 – Br (Boiling point)

b. CH3Cl < CH2Cl2 < CHCl3 < CCl4 (density) c. CH3Cl < CH3F < CH3Br < CH3I (density) d. CCl4 < CHCl3 < CH3Cl < CH2Cl2 (dipole-moment) A, B

9. Among the following pair of reactions in which pair second reaction is more reactive than first for SN1 reaction?

a. Me3C – Cl + H2O and Me3C – Br + H2O b. Me3C–Cl+CH3OH and Me3C – Cl + CH3COOH

c. OHClCMe 2)M1(

3 and OHClCMe 2)M2(

3 d. Me3C – Cl + CH3SH and Me3C – F + CH3SH

A,C Sol. A = Bromide more reactive; C = Concentration of Halide will increase Rate 10. Predict the pair in which 2nd will undergo solvolysis (in aqueous ethanol) more rapidly.

(I) II I II a. b. c. d. B,C,D

Br Cl

Br Br

O

Br CH2Br Br Cl



SECTION – E (Matrix Type) No Negative Marking

This Section contains 3 questions. Each question has four choices (A, B, C and D) given in Column I and five statements (p, q, r, and s) in Column II. Any given statement in Column I can have correct matching with one or more statement(s) given in Column II. 8 × 3 = 24 Marks

1. Match List – I with List – II (Single Match)

Column – I (Statement) Column – II (Reason)

(A) H2S is weaker nucleophile than HS

Θ

(p) Bulky group present on nucleophilic centre

decreases nucleophilicity

(B) 3

Θ

HC is stronger nucleophile than 2

Θ

HN (q) Nucleophilicity decreases on going from left

to right in the period of periodic table

(C)

PR3 is stronger nucleophile than

NR3 (r) A species with negative charge is a stronger

nucleophile than a similar species without a negative charge

(D) Θ

3

|3 OH

CH

CCH is weaker nucleophile than

Θ

3 O CH

(s) Nucleophilicity increases on going down in the group of the periodic table

Sol. A – r; B – q; C – s; D – p 2. Match the Column I with Column II.

Column I Column II

(A) CH3(CH2)3CN and (CH3)3CCN (p) Position isomers (B) CH3CH2CH2OCH3 and CH3CH2OCH2CH3 (q) Chain isomers (C) 3

3

|3 OCHH

CH

CCH and CH3CH2CH2 – O – CH3 (r) Functional isomers

(D)

CH2 = CH – OH and

(s) Metamers

Sol. A – (q); B – (s) or (q); C – (p), (s) ; D– (r) 3. Match Column (I) with Column (II)

(a) (p) Nucleophilic substitution (b) (q) Electrophilic substitution (c) (r) Cation intermediate (d) (s) Free radical substitution

O

+ Ph – CH2 – Cl AlCl3

CH2 – Ph

+ Ph Cl

O

AlCl3 C – Ph

O

H3C – C – CH3

CH3

CH3

Br2, hv CH3 – C – CH2 – Br

CH3

CH3

Br KOH (aq.) CH3 – C – CH3

OH CH3 CH3 H3C

CH3



Sol. A – (q), (r); B – (q), (r) ; C – (p), (r); D – (s)

SECTION – F (Integer Type) No Negative Marking

This Section contains 10 questions. The answer to each question is a single digit integer ranging from 0 to 9. 10 × 5 = 50

1. The total number of methyl ‘CH3’ groups in the major product of reaction

3

3|

Na 3

Dry ether|

CH

CH C Cl

CH

Sol. 2 Tertiary alkyl halide gives alkene in Wurtz reaction.

3 2

3 3| |

Na 3 3

Dry ether| ||

CH CH

CH CH Cl CH C

CH CH

2. Total number of alkenes structure which will show geometrical isomerism of molecular formula C6H12. Sol. 4

(i) CH3 CH = CH CH2 CH2 CH3 (ii)

3

3 3|

CH CH CH CH CH

CH

(iii)

3

3 2 3|

CH CH C CH CH

CH

(iv) CH3 CH2 CH = CH CH2 CH3

[1-hexene; 2,3-dimethylbut-2-ene; 2,3-dimethylbut-1-ene; 2,2-dimethylbut-1-ene do not show geometrical isomer]

3. How many chiral carbons are there in Reserpine (in antipsychotic drug)?

Sol. 8

4. The number of possible enantiomeric pairs that can be produced during monochlorination of 2-methylbutane is

Sol. 2; 32

|

3 CHCHH

ClCH

CCH

2

; 3

||

3 CHH

Cl

CH

CH

CCH

3

O

O

O

O

N

N H

O

O

O O

O

O

O

O

O

N

O

O

O O

O

N H

C



5. How many optical isomers are possible for the compound?

F

BrCl

C

Sol. 2 (single chiral) 6. How many meso isomers of C4H8Cl2 will be formed? Sol. Only one meso possible 7. How many of the following are good substrate for Both SN1 & SN2

(A) (B) CH3Cl (C) CH3 – O – CH2 – Br (D) CH2 = CH – CH2 – Cl

(E) ClCH

O

CCH 2

||

3 (F) (G) (F3C)3C – Cl (H)

Sol. 3; (A); (C); (D) 8. How many of the following give yellow ppt. with AgNO3 + aq.KOH

(A) CH2 = CH – Br (B) CH2 = CH – CH2Br (C) CH3 – CH2 – CH2I (D) (CH3)3C – Br (E) (F) CH3 – CH = CH – Br (G)

Sol. 4; (b); (c); (d), (g) 9. How many dimethyl cyclobutane will be possible (including stereoisomers)? Sol. 6 10. How many CH3MgBr molecules are required for the given molecule

Sol. 4

H – C – Cl

H – C – Cl

CH3

CH3

CH3

CH3

cis(meso) Trans (d, )

(3)

CH3

H3C

cis-trans (2)

CH3

CH3

(1)

HC C

CH

C

O

CH2

COOH

OH

CH2Cl

C Cl

C2H5

CH3

Cl

CH2Cl

CH2 – I

H – C C

CH

C

O

CH2

COOH

OH

acidic Acidic

electrophilic centre

acidic

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Isomerism Organic Halide - Dr. Sangeeta Khanna€¦ · 02.08.2017 · Dr. Sangeeta Khanna Ph.D 1 CHEMISTRY COACHING CIRCLE D:\Important Data\2017\+2\Organic\Grand Test\+2 Grand Test-V.doc