1 GENERAL ORGANIC CHEMISTRY (REVISION)
EXERCISE - 2 : PREVIOUS YEAR JEE MAINS QUESTIONS
1. Which one of the following compounds is non- Hence, acidic strength order will be
aromatic? (2021-02-24/Shift-2) Ka : (ii) > (iii) > (iv) > (i)
1 2 3 4
3. In C H 2 C C H C H3 molecule, the hybridization
(a) of carbon 1, 2, 3 and 4 respectively, are:
(2021-02-26/Shift-2)
(a) sp , sp, sp , sp
2 2 3
(b) sp3, sp, sp3, sp3
(b) (c) sp2, sp3, sp2, sp3
(d) sp2, sp2, sp2, sp3
Ans. (a)
(c)
Sol.
(d)
Ans. (a)
Sol. 4. Among the following, the aromatic compounds are:
(2021-03-16/Shift-1)
contains sp3 - C atom. So it is non-planar & hence non
aromatic.
All other options follow Huckel’s rule i.e.
(4n 2) electrons. So all are aromatic compounds.
2. The correct order of acid character of the following Choose the correct answer from the following options
compounds is: (2021-02-25/Shift-2) (a) (A) and (B) only (b) (B) and (C) only
(c) (A), (B) and (C) only (d) (B), (C) and (D) only
Ans. (b)
Sol.
6 electron
(a) IV > III > II > I (b) II > III > IV > I
(c) III > II > I > IV (d) I > II > III > IV
Ans. (b)
Sol. Stability of conjugate bases : 6 electron
5. Assertion A: Enol form of acetone [CH3COCH3] exists
in < 0.1% quantity. However, the enol form of acetyl
acetone [CH3COCH2OCCH3] exists in approximately
15% quantity.
Reason R: Enol form of acetyl acetone is stabilized by
intramolecular hydrogen bonding, which is not
possible in enol form of acetone.
GENERAL ORGANIC CHEMISTRY (REVISION) 2
Choose the correct statement: resonance? (2021-07-22/Shift-2)
(2021-03-16/Shift-1)
(a) Both A and R are true but R is not the correct (a) CH3CH2OCH = CH2
explanation of A
(b) Both A and R are true and R is the correct
explanation of A (b)
(c) A is true but R is false
(d) A is false but R is true (c) CH3CH2CH2CONH2
Ans. (b) (d) CH3CH2CH = CHCH2NH2
Sol. Ans. (d)
Sol. CH3CH2CH = CHCH2NH2
No conjugation is present
9. Which of the following molecules does not show
stereoisomerism? (2021-07-22/Shift-2)
(a) 3, 4-Dimethylhex-3-ene
(b) 3-Methylhex-1-ene
(c) 3-Ethylhex-3-ene
(d) 4-Methylhex-1-ene
Ans. (c)
Sol.
6. Compound with molecular formula C3H6O can show :
(2021-03-18/Shift-1)
(a) Both positional isomerism and metamerism
(b) Metamerism
(c) Functional group isomerism
(d) Positional isomerism
Ans. (c)
Sol. C3H6 DOU = 1
CH3 - CH3 - CH = O and CH3 C CH3
||
O
are functional isomer.
7. In the following molecule,
10. Which one among the following resonating structures
Hybridisation of Carbon a, b and c respectively are: is not correct? (2021-07-25/Shift-1)
(2021-03-18/Shift-2)
(a) sp3, sp, sp (b) sp3, sp, sp2
(c) sp3, sp2, sp (d) sp3, sp2, sp2 (a)
Ans. (d)
Sol. a sp3
b sp2
c sp2
8. Which of the following compounds does not exhibit
3 GENERAL ORGANIC CHEMISTRY (REVISION)
(2021-07-27/Shift-2)
Ans. (c)
(b) Sol. Hyperconjugation is permanent effect. This statement
is true
(CH 3 C H 2 ) involve Csp2 H1s bond with empty 2p
orbital. This statement is false.
(c)
(d) 13.
Ans. (a)
Sol. Options (b), (c), (d) are resonating structures to each The correct order of stability of given carbocation is:
other while Option (a) do not represent correct (2021-07-27/Shift-1)
structure due to positive charge on adjacent atoms. (a) A > C > B > D (b) D > B > C > A
(c) D > B > A > C (d) C > A > D > B
11. Which among the following is the strongest acid? Ans. (a)
(2021-07-25/Shift-2) Sol.
(a) CH3CH2CH2CH3 (b)
(c) (d)
14. Which one of the following compounds is non-
Ans. (d) aromatic? (2021-08-26/Shift-2)
Sol. Conjugate base of compund (d) is aromatic hence it is
most acidic compound.
(a) (b)
12. Given below are two statements: (c) (d)
Statement I: Hyperconjugation is a permanent effect.
Statement II: Hyperconjugation in ethyl cation Ans. (c)
Sol.
(CH 3 C H 2 ) involves the overlapping of Csp2 H1s
bond with empty 2p orbital of other carbon.
Choose the correct option
(a) Both statement I and statement II are false
(b) Statement I is incorrect, but statement II is true
(c) Statement I is correct, but statement II is false
(d) Both Statement I and statement II are true
GENERAL ORGANIC CHEMISTRY (REVISION) 4
18. The number of acyclic structural isomers (including
15. The number of stereoisomers possible for geometrical isomers) for pentene are ______
1, 2-dimethyl cyclopropane is: (2021-07-22/Shift-2)
(2021-08-26/Shift-2)
(a) One (b) Four Ans. 6.00
(c) Two (d) Three Sol.
Ans. (d)
Sol.
19. The number of sigma bonds in
H 3 C C CH C C H is _________.
|
H
(2021-07-25/Shift-1)
16. Choose the correct name for compound given below: Ans. 10.00
Sol. Number of sigma bonds are 10 in given compound
(2021-08-31/Shift-1)
(a) (4E)-5-Bromo-hex-4-en-2-yne
(b) (2E)-2-Bromo-hex-4-yn-2-ene
(c) (2E)-2-Bromo-hex-2-en-4-yne
(d) (4E)-5-Bromo-hex-2-en-4-yne 20. The dihedral angle in staggered form of Newman
Ans. (c) projection of 1, 1, 1-Trichloro ethane is ......... degree.
Sol. (Round off to the nearest integer)
(2021-07-27/Shift-2)
Ans. 60.00
Sol.
17. The total number of C–C sigma bond/s in mesityl
oxide (C6H10O) is ............... (Round off to the Nearest
Integer) (2021-03-17/Shift-2) 21. Which of the following is an aromatic compound?
Ans. 5.00
(2021-03-17/Shift-1)
Sol.
5 GENERAL ORGANIC CHEMISTRY (REVISION)
(a) (b)
(b)
(c) (d)
Ans. (b)
Sol.
(c)
6 electron system
It is aromatic in nature. (d)
Ans. (d)
Sol. Metamers are compounds which have different alkyl
groups present along both side of polyvalent
22. functional group.
Only options 4 represent metamers
Among the given species the resonance stabilised
carbocations are: (2021-07-20/Shift-1)
(1) These are chain isomers
(2) Not isomers having different molecular formula
(a) (C) and (D) only
(3) Position isomers
(b) (A), (B) and (D) only
(c) (A) and (B) only
24. Arrange the following conformational isomers of
(d) (A), (B) and (C) only
n-butane in order of their increasing potential energy:
Ans. (c)
Sol. Positive charge is in conjugation with pi bond in the A
and B only hence only A and B are resonance stabilized
carbocation.
(2021-08-31/Shift-2)
(a) II < III < IV < I (b) I < IV < III < II
(c) II < IV < III < I (d) I < III < IV < II
Ans. (d)
Sol. More stable less potential energy.
Stability order: I > III > IV > II
23. Which one of the following pairs of isomers is an
So Potential energy: II > IV > III > I
example of metamerism? (2021-07-20/Shift-2)
(a) 25. Which one of the following compounds is aromatic in
nature?
GENERAL ORGANIC CHEMISTRY (REVISION) 6
26. Mesityl oxide is a common name of :
(2021-09-01/Shift-2) (2021-03-17/Shift-1)
(a) 4-Methyl pent-3-en-2-one
(b) 2,4-Dimethyl pentan-3-one
(a) (b) (c) 3-Methyl cyclohexane carbaldehyde
(d) 2-Methyl cyclohexanone
Ans. (a)
Sol.
O
(c) (d) 4 ||
CH 3 CH CH C CH 3
5 | 3 2 1
Ans. (a,d) CH 3
Sol. (Mesityl oxide)
4-methyl pent-3-en-2-one
GENERAL ORGANIC CHEMISTRY (REVISION) 7
27. The isomeric deuterated bromide with molecular
formula C4 H 8 DBr having two chiral carbon atoms is
(JEE Main 2023)
(a) 2–Bromo–1–deuterobutane
(b) 2–Bromo–2–deuterobutane
(c) 2–Bromo–3–deuterobutane
(d) 2–Bromo–1–deutero–2–methylpropane
Ans. (c)
Sol.
28. Compound from the following that will not produce
precipitate with AgNO3 is (JEE Main 2023)
(a)
(b)
(JEE Main 2023)
Ans. (2)
(c)
(d)
Ans. (c)
Sol.
Sol.
29. The total number of chiral compound/s from the
following is ________.
30. The increasing order of pK a for the following phenols
is
(1) 2, 4-Dinitrophenol
(2) 4-Nitrophenol
(3) 2, 4, 5-Trimethylphenol
GENERAL ORGANIC CHEMISTRY (REVISION) 8
(4) Phenol 33. The correct order in aqueous medium of basic strength
(5) 3-Chlorophenol (JEE Main 2023) in case of methyl substituted amines is:
(a) 3 > 4 > 5 > 1 > 2 (JEE Main 2023)
(b) 2 > 1 > 5 > 4 > 3 (a) Me2NH > MeNH2 > Me3N > NH3
(c) 1 > 2 > 4 > 5 > 3 (b) Me2NH > Me3N > MeNH2 > NH3
(d) 1 > 2 > 5 > 4 > 3 (c) NH3 > Me3N > MeNH2 > Me2NH
Ans. (d) (d) Me3N > Me2NH > MeNH2 > NH3
Sol. Order of acidity for following phenol is Ans. (a)
Sol. In aqueous medium basic strength is dependent on
electron density on nitrogen as well as solvation of
cation formed after accepting H+. After considering all
these factors overall basic strength order is Me2NH >
MeNH2 > Me3N > NH3
34. Match List I with List II
- M and – I increases acidity List I (Amines) List II (pKb)
+ M and + I decreases acidity. A. Aniline I. 3.25
31. The correct order of pK a values for the following B. Ethanamine II. 3.00
compounds is: C. N-Ethylethanamine III. 9.38
D. N, N-Diethylethanamine IV. 3.29
Choose the correct answer from the options given
below :- (JEE Main 2023)
(a) A-I, B-IV, C-II, D-III
(b) A-III, B-II, C-I, D-IV
(c) A-III, B-II, C-IV, D-I
(d) A-III, B-IV, C-II, D-I
Ans. (d)
(JEE Main 2023) Sol.
(a) c > a > d > b (b) b > d > a > c
(c) b > a > d > c (d) a > b > c > d
Ans. (b)
Sol. Due to –M effect of – NO2 group, it increases acidity
+M effect of N (CH 3 ) 2 decreases acidity.
1
Hyperconjugation of isopropyl decrease acidity Basic Strength
order of acidic strength pK b
(c) > (a) > (d) > (b) Order for pKb: A > B > D > C
32. The correct order for acidity of the following hydroxyl
compound is:
A. CH 3OH
B. (CH 3 )3 COH
Choose the correct answer from the options given
below: (JEE Main 2023)
(a) D > E > C > A > B
(b) E > D > C > B > A
(c) E > C > D > A > B
(d) C > E > D > B > A
Ans. (c)
Sol. E > C > D > A > B
