Dr. Sangeeta Khanna Ph.D 1Dr. Sangeeta Khanna Ph.D 2 CHEMISTRY COACHING CIRCLE D:\Important Data\2019\+1\Org\Test\Grand Test-6\Grand Test-6.doc Topic: IUPAC Naming, Isomerism, General

$Page 1: Dr. Sangeeta Khanna Ph.D 1Dr. Sangeeta Khanna Ph.D 2 CHEMISTRY COACHING CIRCLE D:\Important Data\2019\+1\Org\Test\Grand Test-6\Grand Test-6.doc Topic: IUPAC Naming, Isomerism, General$
Dr. Sangeeta Khanna Ph.D 1 CHEMISTRY COACHING CIRCLE D:\Important Data\2019\+1\Org\Test\Grand Test-6\Grand Test-6.doc

Dr. Sangeeta Khanna Ph.D


Topic: IUPAC Naming, Isomerism, General Organic Chemistry

READ THE INSTRUCTIONS CAREFULLY

1. The test is of 2 hour duration. 2. The maximum marks are 241. 3. This test consist 55 questions.

Section – A (Single Correct Choice Type) Negative marking

This Section contains 40 multiple choice questions. Each question has four choices A), B), C) and D) out of which ONLY ONE is correct. (Mark only one choice) (40 × 4 = 160 Marks)

1. Which class of the organic compounds do the following belong to?

a. Alicyclic b. Acyclic c. Benzenoid d. Heterocyclic D Sol. All are heterocyclic compounds because these have N, O and S as hetero-atoms with carbon in ring. 2. Select the correct IUPAC name of:

a. 3–Ethyl–5–(2,2–dimethylbutyl) decane b. 5–(2,2–Dimethylbutyl) –3–ethyl decane c. 5–(2–Ethylbutyl) –3,3–dimethyl decane d. All are correct C Sol.

From lower part and right side both give longest carbon chain of 10C – atom, but lower part gives more number of side chains.

3. Select the correct IUPAC name of the following compound

a. 3–Hydroxy–6–methyloctane b. 3–Methyl–6–hydroxyoctane

b. 6–Hydroxy–3–methyloctane d. 6–Methyloctan – 3 – ol D Sol. OH is alcoholic group – ol, the lowest location of OH is ‘3’. So, methyl is at locant ‘6’

CH3 – CH2 – CH2 – CH2 – CH2 – CH – CH2 – CH – CH2 – CH3

CH2 – CH3

CH2

C H3C CH3

CH2 – CH3

CH3 – CH2 – CH2 – CH2 – CH2 – CH – CH2 – CH – CH2 – CH3

CH2 – CH3

CH2

C H3C CH3

CH2 – CH3 1 2

3

4

5 6 7 8 9 10

1 2 3 4

H3C– CH2 – CH – CH2 – CH2 – CH – CH2 – CH3

OH CH3

N H

O S



4. For the following reactions:

(i) OHKBrCHCHCHKOHBrCHCHCH 223.alc

223

(ii) (iii) Which of the following statement is correct? a. (i) is elimination, (ii) is substitution and (iii) is addition b. (i) is elimination, (ii) and (iii) are substitution c. (i) is substitution, (ii) and (iii) are addition reactions d. (i) and (ii) are elimination reactions and (iii) is addition reaction A

5. The species 33 HCHCCH

is less stable than

a. (CH3)3C+ b. 223 HCCHCH

c. 23 HCCH

d. 3CH

A

Sol.

3

3

CH

CH

CCH

|

|3

has 9 - H and more electron donating group.

6. Arrange in the order of decreasing pKa. P. F – CH2CH2COOH Q. Cl – CH2 – CH2 – COOH R. F – CH2 – COOH S. Br – CH2 – CH2 – COOH Correct answer is:

a. Q > S > P > R b. P > R > S > Q c. R > Q > P > S d. S > Q > P > R D

7. Consider the following species:

a. HOΘ

(B) Θ

3 OCH (C) 3

Θ

HC (D) 2

Θ

HN

Arrange these species in their decreasing order of nucleophilicity. a. C > D > B > A b. B > A > C > D c. A > B > C > D d. C > A > B > D A 8. Arrange the following in increasing order of stability. a. I < II < III b. II < I < III c. I < III < II d. II < III < I C

Sol. As number of - H increases stability increases

+ Br2

Br

Br

Br

CH3 H3C

+ KOH aq.

OH

CH3 H3C

+ KBr

(I) (II) (III)



9. In which of the following molecules -electron density in ring is maximum? a. b. c. d. B

Sol. Θ

O is better donar than – NH2 and – OCH3

10. The decreasing order of stability of following is a. P > Q > R > S b. S > R > Q > P c. Q > S > R > P d. Q > R > S > P B Sol. Stability of anion increases with – I effect.

11. The structure of 2,6-Dimethyl octa-2,6-diene is

a. b. c. d.

B

12. Which of the following resonating structures is most unstable? a. b. c. d. B Sol. (b) is most unstable because both parts of cycle are Anti aromatic 13. The least stable carbanion among the following is

a. 3

Θ

HC b. 3

Θ

3 CHHCCH c.

3

|

Θ

3 CH

CH

CCH

3

d.

Θ2

|

|HC

Cl

Cl

CCl

C

Sol. Due to maximum +I effect 14. Identify the strongest nucleophile.

4 - H 10 - H 6 - H

CH2

CH3

CH2

CH2Cl

CH2

CHCl2

CH2

CCl3

(P) (Q) (R) (S)

NO2 O Θ

NH2 OCH3



a. F– b. Cl– c. Br– d. I–

D

15. The groups which can exert both + M and – M effect

a. nitro b. cyano c. ester d. All

C

16. Which of the following is correct order of stability?

(i) 32 CHHCCHCH

(ii)

(iii) 22 HCCHCH

(iv)

223 CHCHCH

a. (i) > (ii) > (iii) > (iv) b. (ii) > (i) > (iii) > (iv) c. (iv) > (iii) > (ii) > (i) d. (ii) > (iii) > (i) > (iv) B

17. The most stable conformation of cyclohexane is:

a. Boat b. Half-chair c. Chair d. Twist-boat

C

18.

a. position isomers b. chain isomers c. functional isomers d. metamers D

19. In ethylene glycol 2|

2|

H

OH

CH

OH

C which conformation is more stable?

a. Anti staggered b. Gauche c. Partially eclipsed d. Eclipsed B

20. Phenol exists in 100% enol form. The reason is

a. Phenol is more stable than its keto form as phenol is aromatic b. Phenol has high b.p. c. Phenol is stabilized by H-bonding. d. Keto form is non planar A

21. Which of the following exhibits geometrical isomerism? a. b. c. d. A

C = C = C = C

H3C

H

CH3

H

C = C = C

H

CH3 CH3

H

C = C = C

H

CH3 CH3

CH3 C = C = C = C

H3C

H

CH3

CH3

C O

O

and C O H

O

CH2 = CH – CH



22. In which of the following Keq > 1 a. b. c. d. B

23. C – C single bond length would be minimum in:

a. |

|CC b.

|

|

|

CC c. ||CC d. C – C

D Sol. Both carbon atoms are sp hybridized. 24. In which of the following lone-pair shown is involved in resonance.

a. CH2=CH–CN b. c. d.

D 25. Among the following carbon radicals, the stability decreases in the order

a. (CH3)3C > CH2 = CH – CH2 > (CH3)2CH > CH3CH2 > HCCH2

b. HCCH2

> (CH3)3C > (CH3)2CH > CH2 = CH – CH2 > CH3CH2

c. CH2 = CH – CH2 > (CH3)3C > (CH3)2CH > CH3CH2 > HCCH2

d. (CH3)3C > (CH3)2CH > CH3CH2 > CH2 = CH – CH2 > HCCH2

C

OH

OH

H H

H

H

OH OH

H

H

CH3

CH3 H

CH3

H

CH3

OH

OH

H

H

H

H

OH

HO

Cl H

H

H

OH

OH

Cl

H

N N O



26. Which of the following is the correct order of decreasing stability?

a. CH ΘC > CH2 = ΘCH > CHΘ3 b. CHΘ

3 > CH2 = ΘCH > CH ΘC

c. Θ2

ΘΘ3

CHCHCCHCH d. CH2 = Θ3

ΘΘ CHCCHCH

A

Sol. negative charge on more electronegative atom is more stable.

27. Which of the following position is reactive for electrophilic attack

a. 1, 3, 8 b. 1, 3, 5 c. 10, 8, 6 d. 1, 3, 6

B

28. The compound 3

3

|

3

|3 CHH

CH

CH

CH

CCH have

a. Twelve 1° hydrogen atoms only b. Two 2° and twelve 1° hydrogen atoms

c. Two 3° hydrogen atoms only d. Twelve 1°- and Two 3°-hydrogen atoms

D

29. All the functional groups present in given compound are

a. Ether, alkene, alcohol b. Alcohol, ketone, alkene, ether, ester

c. Alcohol, ketone, ester, alkene d. Ether, amine, keton, ester

B

30. Which of the following alkenes is the most stable?

a. b. c. d.

C

Sol. Conjugated dienes are most stable

31. Which of the following can exhibit geometrical isomerism:-

a. Ethene b. Propane c. 1-Butene d. Dimethyl cyclobutane

D

Sol.

NH – C

1 2

3

4 5

O 10 9

8

7 6

CH3

CH3

CH3

CH3

CH3

HOH2C

O

O

OCH3

Cortisone

O

O



32. Which of the following pair of structures represent the same compound?

a.

b.

c.

d.

A

33. An alkane (molecular weight 72) upon chlorination gives one monochlorination product. The alkane is

a. 2-Methylbutane b. n-Pentane

c. 2, 2-Dimethylpropane d. Cyclohexane

C

Sol. ClCH

CH

CH

CCHCH

CH

CH

CCH 2

|

|3

Cl3

|

|3

3

3

2

3

3

; Cyclohexane C6H12 (M.Wt. = 84]

34. The most stable carbocation among the following

a. b.

c. d.

C

Sol. Both C and D are tertiary carbocations but D is less stable than C due to the presence of an electron

withdrawing group.

35. The ortho/para directing group for benzene, among the following is:

a. –COOH b. –CN c. –COCH3 d. –NHCOCH3

D

Sol. NHCOCH3 is o, p – directing while all others are m – directing.

36. Which of the following is most stable?

a. 23 HCOCH

b. 22 HCCHCH

c. 22|

HCH

F

C

d. 22|

HCH

OH

C

A

Sol. Back bonding 23 CHOCH

C = C

CH2 = CH

H H

CH3

, C = C CH2 = CH

H

H

CH3

H

H C = C

Cl

CH2Cl ,

H

H C = C

Cl

CH2Cl

C = C CH3CH2

H H

, CH3CH2

C = C

CH3

H CH2CH2CH3

H

CH3 – CH = CH – CH3 and

CH3

NO2



37. In the case of following alkenes, the decreasing order of stability

3

I

||3 CH

H

C

H

CCH

)II(

3

|

|3 HC

H

C

H

CHC

III

2

|

3 CH

CH

CCH

3

a. I > II > III b. III > II > I c. I = II > III d. III > I > II B

Sol.

I

butene2cis

3

H|

H|3 HCCCHC

II

butene2trans

3

H|

H

|3 HCCCHC

III

buty leneiso2

HC|

3 HCCHC

3

Since ,transcis trans-2-butene (II) is more stable than cis – 2 – butane (I).

38. Why does cis-2-butene have a molar heat of hydrogenation of 120 kJ while trans-2-butene has 116 kJ?

a. The cis isomer is more stable than the trans due to steric interactions.

b. The trans isomer is more stable than the cis due to less steric interactions

c. The double bond in the trans isomer has more potential energy

d. Trans-2-butene has a higher molecular weight.

B

Sol. The lower heat of hydrogenation of the trans isomer indicates that it is more stable ruling out answers A

and C. Molecular weight has nothing to do with bond stability and both isomers have the same molecular

weight ruling answer D. Answer B makes sense. When the larger substituents are on the same side of

the double bond there is steric interaction which decreases the stability of the molecules.

39. Which of the following statement is not true for Benzyne intermediate?

a. Its triple bond is formed by P – P and sp2 – sp2 lateral overlapping along with a -bond (sp2 – sp2). b. Triple bond have sp hybridised carbon

c. It has 6 delocalised electron. d. Its formula is C6H4 B

40. Which of the following has chiral carbon

a. 2||

2|

H

Cl

CH

CH

CH

Cl

C

3

b. 32|

23 CHCHH

OH

CCHCH

c. 3|

2|

CHH

CH

CH

Cl

C

3

d. 32|

2|

CHCHH

OH

CH

Cl

C

D

Number of hyperconjugative structures

6 6 6



SECTION – D More than One Answer (No Negative Marking) This Section contains 6 multiple choice questions. Each question has four choices A), B), C) and D) out of which ONE OR MORE may be correct. 6 × 5 = 30 Marks

1. The correct statements for alkyl carbocations are

a. paramagnetic b. sp2 hybridised c. diamagnetic d. formed by heterolytic cleavage B,C,D

2. Name of some compounds are given which one is not correct in IUPAC system?

a.

etanethy lhep4Methy l3Chloro3

32

|

|

|

23 CHCHH

CH

CH

CHCH

CH

Cl

CCHCH

3

32

b.

ol1opanDimethy lpr1 ,1

3

|

|23 CH

CH

OH

CCHCH

3

c.

ene1methy lbut3Ethy l2

3

3

|

2

||23 CHH

CH

C

CH

CCHCH

d. y ne2Methy lpent4

233 )CH(CHCCCH

A,B Sol. (a) Ethyl should be written first (b) 2-Methylpropan-2-ol 3. Which of the following statement is correct:-

a. Alkene and Benzene act as Nucleophile b. Addition of electrophile on alkene is faster than alkyne due to formation of stable intermediate

carbonium ion.

c. Θ2

NO is an amphident nucleophile

d. Triplet carbene is paramagnetic A,B,C,D

4. Which of the following is meta directing group for benzene?

a. b. c. d.

A,B,D 5. Which of the following represents functional isomers?

a. Alcohols and ether b. Nitroalkanes and alkyl nitrites (R – O – N = O) c. Carboxylic acid and ester d. Glucose and fructose A,B,C,D

6. Which of the following is correct? a. b.

C – O – CH3 + E

O

O – C – CH3 + E

O

Ea[1]

Ea[2]

CH3+

(CH3)3C+

C – Cl

Reaction coordinate

En

erg

y Ea[1]

Ea[2] CH3

(CH3)3C+

C – Cl

Reaction coordinate

En

erg

y

C N + E

CF3 + E



c. d. A, D

SECTION – E (Matrix Type) No Negative Marking

This Section contains 2 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. (2 × 8 = 16 Marks)

1. Match Column – I with Column – II. (One or More than One Match)

Column – I Column – II

(A) CH3 – CH2 – O – CH2CH3 and CH3 – O – CH2 – CH2 – CH3 (p) Tautomers

(B) CH3CHO & CH2 = CH – OH (q) Metamers

(C) CH3COOH and HCOOCH3 (r) Functional Isomers

(D)

(s) Geometrical Isomers

Sol. A Q; B P & R; C R; D S 2. Match the column – I with column – II. (One or More than One Match)

Column – I Column - II

(A)

(p)

All atoms sp2 hybridised

(B)

(q)

Heterocyclic

(C)

(r)

Antiaromatic

(D)

(s)

Homocyclic

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

CH3

H

C = C

CH3

H

and CH3

H C = C

CH3

H

O

NH

NH2

Ea[1]

Ea[2]

CH2 = CH

C – Cl

Reaction coordinate

En

erg

y

Ea[1]

Ea[2]

C – Cl

Reaction coordinate

En

erg

y

CH3 – CH – CH3

CH2



SECTION – F (Integer Type) No negative Marking

This Section contains 7 questions. The answer to each question is a single digit integer ranging

from 0 to 10. 7 × 5 = 35 Marks

1. The number of chiral centers present in 3, 4-dibromo-2-pentanol is: Sol. 3 2. The number of alkynes possible with molecular formula C5H8 is: Sol. 3 3. Total number of isomers excluding stereoisomers of C4H10O. Sol. 7

ol1Butene

2223 OHCHCHCHCH

;

ol-2-Butan)(d/ activ e) Optically(

32|

3 CHCHH

OH

CCH

l

OHCHH

CH

CCH 2|

3

3

ol2propanmethy l2

|

|3 OH

CH

CH

CCH

3

3

; ethane ethoxy

3223 CHCHOCHCH ; propane methoxy1

3223 CHCHCHOCH

;

3

3

CH

CH

/\

CHOCH3

4. What is the ratio of and bond in methyl Benzene. Sol. 5

53

15

5. How many dichloropropene can exist? (including stereoisomer) Sol. 7

, ,

Br

Br OH

H – C – H

H

H

H

H

H

H

C = CH – CH3;

H

Cl

C = C – CH3;

Cl

cis/trans

CH = CH – CH2;

Cl Cl

cis/trans

CH2 = C – CH2;

Cl

Cl

CH2 = CH – CH

Cl

Cl Cl

Cl



6. How many of the following compounds are more reactive than Benzene for electrophilic substitution reaction. (a) (b) (c) (d) (e) (f) (g)

Sol. 4 (b, d, e, g) 7. How many of the following statements are correct

(a) Heat of hydrogenation of trans alkene is less than cis alkene. (b) cis alkene is generally more polar than Trans alkene (c) Both cis & Trans alkene have same Boiling point. (d) Both the double bond have cis-arrangement (e) (f) 1,3-Dichlorobutane have cis/trans Isomers (g) Both cis & trans alkene are diastereomers (h) Both cis and Trans alkene have same solubility

Sol. 5 a, b, d, e, g

Cl CH3 NO2 O – N = O

O – C – R

O

CF3

NH – C – R

O

CH3

H

C = N – OH C = N – OH have geometrical isomer



8. Which of the following alkenes is the most stable?

a. Ethylene b. cis-2-butene c. 2-methyl-2-butene d. 2, 3-dimethyl-2-butene

D

Sol. According to the table 2, 3-dimethyl-2-butene is the most stable alkene because it has the lowest heat of hydrogenation. This follows the rule that the most substituted alkene is the most stable.

Documents

Dr. Sangeeta Khanna Ph.D 1Dr. Sangeeta Khanna Ph.D 2 CHEMISTRY COACHING CIRCLE D:\Important Data\2019\+1\Org\Test\Grand Test-6\Grand Test-6.doc Topic: IUPAC Naming, Isomerism, General