Structure Identification

 Marked Questions may have for Revision Questions.



PART - I : ONLY ONE OPTION CORRECT TYPE

-I: (ONLY ONE OPTION CORRECT TYPE)

1. The degree of unsaturation of following compound C8H12O, C3H5N, C4H8O are respectively :
C8H12O, C3H5N, C4H8O
(A) 4,3,2 (B*) 3,2,1 (C) 2,1,3 (D) 2,2,3
2. Which of the following hydrocarbons give same product on hydrogenation.
(A) 2-Methyl hex-1-ene & 3-Methyl hex-3-ene
(B) 3-Ethyl hex-1-en-4-yne & 2-Methylhept-2-en-4-yne
(C) 3-Ethylcycloprop-1-ene & 1,2-Dimethylcycloprop-1-ene
(D*) 2-Methylbut-2-ene & 3-Methylbut-1-ene

(A) 2- -1- 3- -3-

(B) 3- -1- -4- 2- -2- -4-
(C) 3- -1- 1,2- -1-
(D*) 2- -2- 3- -1-
3. Number of moles of hydrogen will required for complete hydrogenation of one mole of following compound :

(A) 6 (B) 7 (C*) 5 (D) 3

4. How many alkenes on catalytic hydrogenation give isopentane as a product (consider only structural
isomers) ?
( )?
(A) 2 (B*) 3 (C) 4 (D) 5
5. If 1 mole H2 is reacted with 1 mole of the following compound.
1 H2 1

Which double bond will be hydrogenated ?

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

6. Only two isomeric monochloro derivatives are possible for :-
(A) n-Pentane (B) 2,4-Dimethyl pentane
(C) Toluene (D*) 2,3-Dimethyl butane

(A) n- (B) 2,4- (C) (D*) 2,3-

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Structure Identification
7. The number of possible monochloro derivatives of 2, 2, 3, 3-Tetramethylbutane is -
2, 2, 3, 3-
(A) 2 (B) 3 (C) 4 (D*) 1
8. Which of the following alkene gives four monochloro (structural isomer) products after hydrogenation ?
(A) Pent-2-ene (B*) 2-Methylbut-2-ene (C) 3-Methylhex-2-ene (D) 2, 3-Dimethylbut-2-ene
4- ?
(A) -2- (B*) 2- -2- (C) 3- -2- (D) 2, 3- -2-

9. Which of the following compound will give four monochloro (structural) product on monochlorination.

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

O / Zn
10. X 3  +

Y..
The IUPAC name of compound Y is :
(A)2-Cyclohexylbutane (B*)1-Methylpropylcyclohexane
(C) Butylcyclohexane (D)1-Cyclohexylbutane

O / Zn
X 3  +

Y..
Y IUPAC
(A) 2- (B*) 1-
(C) (D) 1-

11. An alkene give two moles of HCHO, one mole of CO2 and one mole of on ozonolysis.

What is its structure?

HCHO CO2

(A) (B*)

(C) (D)

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Structure Identification
12. Which of the following compound on reductive ozonolysis does not give glyoxal as one of the product.

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

13. Compound A (C6H12) does not absorb H2 in presence of Ni. It forms two monochloro isomers on photochemi-
cal chlorination. Its structure can be :
A (C6H12) Ni H2

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

14. Which alkyne will give 3-Ethyl heptane on catalytic hydrogenation.

3-

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

15. Which of the following compound gives bromine water test ?

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

16. Identify a reagent from the following list which can easily distinguish between 1-butyne and 2-butyne.
(A) bromine, CCl4 (B) H2/Ni
(C) dilute KMnO4 (D*) ammonical Cu2Cl2 solution
1- 2-
(A) CCl4 (B) H2/Ni
(C) KMnO4 (D*) Cu2Cl2
17. What simple laboratory test could be performed to distinguish between 1-pentyne and 2-pentyne ? (A*)
the addition of Ag+ in ammonia (B) the addition of H2SO4 in Hg+2
(C) the addition of Br2 in CCl4 (D) the addition of H2 on a Pt catalyst.
1- 2-
(A*) Ag+ (B) Hg+2 H2SO4
(C) CCl4 Br2 (D) Pt H2
18. Farnesene is a compound found in the waxy coating of apples. On hydrogenation it gives 2,6,
10-Trimethyl dodecane. On ozonolysis it gives one mole acetone, one mole of formaldehyde, one mole of 2-
Methylpentanedial and one mole of 4-Oxopentanal. The structure proposed for Farnesene may be
(Farnesene) (apples) (waxy)
2, 6, 10-
2- 4-

(A) (B)

(C*) (D)

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Structure Identification
19. A compound P(C5H6) gives positive Bayer test and on hydrogenation form a hydrocarbon B(C5H10) which
gives only one monochloro product. The compound 'P" is.
P(C5H6) B(C5H10)
'P"

(A) (B) (C*) (D) CHC–CH2–CH=CH2

20. How many products (structural isomers only) are formed by monochlorination of given compound ?

(A) 4 (B*) 3 (C) 5 (D) 6

Ozonolysis
21. An alkene (A)   , A is :

(A)      , A

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

22.

Compound 'X' is :
(A) 1-Methylcyclopropene (B) 1, 4-Dimethylcyclohexa-1,4-diene
(C) 1, 4-Dimethylcyclohexa-1,3-diene (D*) 1, 2-Dimethylcyclohexa-1,4-diene

'X'
(A) 1- (B) 1, 4- -1,4-
(C) 1, 4- -1,3- (D*) 1, 2- -1,4-

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Structure Identification
23. The chemical reactions of an unsaturated compound ‘M’ are given below. Determine the possible structural
formula of ‘M’

(M)

‘M’ ‘M’

(M)

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

PART - II : ONE OR MORE THAN ONE OPTIONS CORRECT TYPE

- II :

24. Which of the following compounds after complete hydrogenation will form three monochloro structural iso-
meric products ?

C  CH
(A) (B) (C*) (D*) |
HC  C – CH – C  CH

25. A organic compound having molecular formula C3H4, react with sodium metal to give a colourless and odourless
gas. Select the correct statements about organic compound.
(A*) It gives Bromine water test
(B*) It reacts with Bayer’s reagent
(C*) It reacts with Tollen’s reagent
(D*) It reacts with Ammonical cuprous chloride.
C3H4

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

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Structure Identification

26.

True statements is/are

(A) Structure of X is

(B*) Structure of X is

(C*) Y on monochlorination produce 3 monochloro structural products.

(D*) Structure of y is

(A) X

(B*) X

(C*) Y, 3

(D*) y

27. Which of the following compound gives 1,4-Dimethyl cyclohexane when undergo catalytic hydrogenation.
1,4-
CH2

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

CH3

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Structure Identification

PART-III : INTEGER TYPE

- III : INTEGER TYPE

28. How many isomeric alkynes on catalytic hydrogenation gives 3-Ethyl-4-methylheptane ?

3- -4-
Ans 3
29. Find the number of structural isomers of fully saturated cycloalkane of molecular formulae C6H12 which give
three monochloro structural products and have cyclobutane ring.
C6H12

Ans. 3
30. How many of the following compounds decolorise Br2 water solution ?
Br2

(I) (II) (III) Me – C  C – Me (IV)

(V) (VII) ` (VIII) Me – CH = CH – Et (IX)

Ans. 5

31.

Calculate sum of number of products formed in the reaction a, b and c.

a, b c
Ans. 5
32. How many alkenes, alkynes and alkadienes can be hydrogenated to form Isopentane (Including all structural
isomers)

Ans. 6
33. ‘n’ number of alkenes yield 2,2,3,4,4-pentamethyl-pentane on catalytic hydrogenation and ‘m’ number of
monochloro structural isomers are possible for this compound.
Report your answer as (n + m).
2,2,3,4,4- ‘n’ (2,2,3,4,4- )
‘m’ (n + m)
Ans. 4

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Structure Identification
34. How many isomeric structural alkene on catalytic hydrogenation gives 3-Methyl hexane.
3-
Ans. 6

H / Ni Cl / h
35. 2 
 P 2 Q (Total number of monochloro structural products).

H / Ni Cl2 / h
2 
 P   Q ( )

Ans. 2
36. How many hydrocarbons having molecular mass 68 can give white precipitate with Tollen's reagent ?
68 ?
Ans. 2

PART - IV : JEE (MAIN) / AIEEE PROBLEMS (PREVIOUS YEARS)

- IV : JEE (MAIN) / AIEEE

37. On mixing a certain alkane with chlorine and irradiating it with ultraviolet light, it forms only one
monochloroalkane. This alkane could be : [AIEEE 2003]
(1) propane (2) pentane (3) isopentane (4*) neopentane.

[AIEEE 2003]
(1) (2) (3) (4*)
38. Of the five isomeric hexanes,the isomer which can give two monochlorinated compounds is ?
[AIEEE 2005]
(1) n–Hexane (2*) 2,3-Dimethylbutane (3) 2,2-Dimethylbutane (4) 2-Methylpentane
[AIEEE 2005]
(1) n– (2*) 2,3- (3) 2,2- (4) 2-
39. In the following sequence of reactions, the alkene affords the compound 'B'
O3 H O
CH3CH = CHCH3  A 2 B compound B is [AIEEE 2008, 3/105]
Zn
B
3 O
H O
CH3CH = CHCH3 
 A 2 B B [AIEEE 2008, 3/105]
Zn
(1) CH3CH3CHO (2) CH3COCH3 (3) CH3CH2COCH3 (4*) CH3CHO
40. Ozonolysis of an organic compound 'A' produces acetone and propionaldehyde in equimolar mixture. Identify
'A' from the following compounds : [AIEEE 2011, 4/120]
(1) 1-Pentene (2) 2-Pentene
(3*) 2-Methyl-2-pentene (4) 2-Methyl-1-pentene
'A'
'A' [AIEEE 2011, 4/120]
(1) 1- (2) 2- (3*) 2- -2- (4) 2- -1-

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Structure Identification
41. Which branched chain isomer of the hydrocarbon with molecular mass 72u gives only one isomer of mono
substituted alkyl halide ? [AIEEE 2012, 4/120]
(1) Tertiary butyl chloride (2*) Neopentane
(3) Isohexane (4) Neohexane
72u
[AIEEE 2012, 4/120]
(1) (2*)
(3) (4)
42. Which compound would give 5-keto-2-methyl hexanal upon ozonolysis ? [JEE Main 2015, 4/120]
5- -2- [JEE Main 2015, 4/120]

(1) (2*) (3) (4)

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