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JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

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Q.1. The number of isomeric tetraenes (NOT containing sp-hybridized carbon atoms) that can be formed from the following reaction sequence is ___________.    (JEE Advanced 2022)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. 2


Q.2. Compound 'A' undergoes following sequence of reactions to give compound 'B'.
The correct structure and chirality of compound 'B' is           (JEE Main 2022)
[where Et is - C2H5]

JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. c
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.3. Identify the correct statement for the below given transformation.          (JEE Main 2022)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) A − CH3CH2CH = CH − CH3, B − CH3CH2CH2CH = CH2, Saytzeff products
(b) A − CH3CH2CH = CH − CH3, B − CH3CH2CH2CH = CH2, Hofmann products
(c) A − CH3CH2CH2CH = CH2, B − CH3CH2CH = CHCH3, Hofmann products
(d) A − CH3CH2CH2CH = CH2, B − CH3CH2CH = CHCH3, Saytzeff products

Ans. c
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.4. Major product 'B' of the following reaction sequence is :          (JEE Main 2022)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. b
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.5. Major product of the following reaction is          (JEE Main 2022)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. d


Q.6. Given below are two statements :          (JEE Main 2022)
Statement I : The presence of weaker π-bonds make alkenes less stable than alkanes.
Statement II : The strength of the double bond is greater than that of carbon-carbon single bond.
In the light of the above statements, choose the correct answer from the options given below:
(a) Both Statement I and Statement II are correct.
(b) Both Statement I and Statement II are incorrect.
(c) Statement I is correct but Statement II is incorrect.
(d) Statement I is incorrect but Statement II is correct.

Ans. b


Q.7. The major product in the reaction          (JEE Main 2022)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) t-Butyl ethyl ether
(b) 2,2-Dimethyl butane
(c) 2-Methyl pent-1-ene
(d) 2-Methyl prop-1-ene

Ans. d


Q.8. The product formed in the following reaction.          (JEE Main 2022)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. b


Q.9. Product 'A' of following sequence of reactions is          (JEE Main 2022)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. d


Q.10. What will be the major product of following sequence of reactions?          (JEE Main 2022)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. c


Q.11. Which one of the following compounds is inactive towards SN1 reaction?          (JEE Main 2022)

(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. c


Q.12. The major product (P) in the reaction          (JEE Main 2022)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE is
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. c


Q.13.
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

The stable carbocation formed in the above reaction is          (JEE Main 2022)
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. c


Q.14. The stereoisomers that are formed by electrophilic addition of bromine to trans-but-2-ene is/are :          (JEE Main 2021)
(a) 2 enantiomers and 2 mesomers
(b) 2 identical mesomers

(c) 2 enantiomers
(d) 1 racemic and 2 enantiomers

Ans. b
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.15. In the reaction given below, the total number of atoms having sp2 hybridization in the major product P is _________.          (JEE Advanced 2021)

Ans. 12
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
Alkene on treatment with ozone (O3) followed by treatment with Zn/H2O gives carbonyl compounds.
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
Carbonyl compounds react with NH2OH to give oximes.
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
There are four sp2-carbon atoms, four sp2-nitrogen atoms and four sp2-oxygen atoms as shown in structures I and II.
Therefore, total number of atoms having sp2-hybridisation are twelve (12).


Q.16. The major product formed in the following reaction of           (JEE Advanced 2021)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. b
It is a case of Birch reduction. Alkynes on reaction with alkali metal in liq. NH3 gives trans-alkene. But terminal alkynes do not get reduced.
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.17. For the following sequence of reactions, the correct products are :          (JEE Main 2021)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. a
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.18. The major product (A) formed in the reaction given below is :          (JEE Main 2021)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. b
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.19. In the following sequence of reactions, the final product D is :          (JEE Main 2021)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) CH3 − CH = CH − CH2 − CH2 − CH2 − COOH
(c) H3C − CH = CH − CH(OH) − CH2 − CH2 − CH3
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. d
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.20.  Excess of isobutane on reaction with Br2 in presence of light at 125ºC gives which one of the following, as the major product?          (JEE Main 2021)
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. d
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
Bromination is highly selective, reactivity order –
3° >> 2° > 1


Q.21. Among the following compounds I-IV, which one forms a yellow precipitate on reacting sequentially with (i) NaOH (ii) dil. HNO3 (iii) AgNO3?          (JEE Main 2021)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) II
(b) IV
(c) I
(d) III

Ans. b
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
Other compounds halide can't be removed because corresponding C+ is highly unstable.


Q.22. The major product formed in the following reaction is :          (JEE Main 2021)JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. a
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
This addition is known as 1, 4-addition.
Mechanism This reaction can undergoes two pathways

JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
Out of the two intermediates formed in two paths, the path B intermediate is more stable as it has more stable carbocation. So, a major product will be formed because of path B.
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
1, 2-addition product is formed at low temperature and will be less stable as the double bond is less substituted. 1, 4-addition is a thermodynamically stable product as the double bond is more substituted. As diene is in excess and HBr is limited in reaction, so diene cannot be formed. So option (b) is incorrect.


Q.23. Metallic sodium does not react normally with :          (JEE Main 2021)
(a) gaseous ammonia
(b) But-2-yne
(c) Ethyne
(d) tert-butyl alcohol

Ans. b
Metallic sodium does not react with 2-butyne because 2-butyne does not have acidic hydrogen.


Q.24. The correct pair(s) of the ambident nucleophiles is(are)          (JEE Main 2021)
(A) AgCN/KCN
(B) RCOOAg/RCOOK
(C) AgNO2/KNO2
(D) AgI/KI
(a) (B) and (C) only
(b) (B) only
(c) (A) and (C) only
(d) (A) only

Ans. c
Ambident ligands are those which have two donor sites but at once it has the ability to donate either site.
Hence in AgCN/KCN, AgNO2/KNO2, CN-, NO2- have two donar sites act as ambident Nu-.


Q.25. Choose the correct statement regarding the formation of carbocations A and B given.          (JEE Main 2021)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) Carbocation A is more stable and formed relatively at faster rate
(b) Carbocation B is more stable and formed relatively at slow rate
(c) Carbocation B is more stable and formed relatively at faster rate
(d) Carbocation A is more stable and formed relatively at slow rate

Ans. c
Carbocation B is more stable as it is secondary carbocation having more number of α-hydrogens and having a greater +I effect.
∴ Carbocation B formed at a faster rate than carbocation A.


Q.26. Which of the following reaction is an example of ammonolysis?          (JEE Main 2021)
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. d
Ammonolysis of alkyl halides is the reaction of an alkyl halide with NH3 which leads to the preparation of amines.
C6H5CH2Cl + NH3 → C6H5CH2NH2


Q.27. Product ''A'' in the chemical reaction is :          (JEE Main 2021)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. b

JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.28.
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
The above reaction requires which of the following reaction conditions?          (JEE Main 2021)
(a) 623 K, Cu, 300 atm

(b) 623 K, 300 atm
(c) 573 K, 300 atm
(d) 573 K, Cu, 300 atm

Ans. b
Chlorobenzene is fused with NaOH at 623 K and 300 atmospheric pressure to get sodium phenoxide.
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.29.
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Identify the reagent(s) 'A' and condition(s) for the reaction          (JEE Main 2021)
(a) A = HCl, ZnCl2
(b) A = HCl; Anhydrous AlCl3
(c) A = Cl2; UV light
(d) A = Cl2; dark, Anhydrous AlCl
3

Ans. c
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.30.
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
The products ''A'' and ''B'' formed in above reactions are :          (JEE Main 2021)

(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. b

JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.31.
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Considering the above reaction, the major product among the following is :          (JEE Main 2021)
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. a

JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.32. Match List - I with List - II.
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
Choose the correct answer from the options given below :          (JEE Main 2021)
(a) (a) → (ii), (b) → (iv), (c) → (i), (d) → (iii)
(b) (a) → (iii), (b) → (iv), (c) → (i), (d) → (ii)
(c) (a) → (iii), (b) → (i), (c) → (iv), (d) → (ii)
(d) (a) → (ii), (b) → (i), (c) → (iv), (d) → (iii)

Ans. a
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.33. For the given reaction :          (JEE Main 2021)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
What is 'A'?

(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) CH3CH2CH2NH2  

Ans. a
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.34.
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
Which of the following reagent is suitable for the preparation of the product in the above reaction?          (JEE Main 2021)
(a) Red P + Cl2
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) NaBH4
(d) Ni/H2 

Ans. b
To reduce the carbonyl groups into alkane, Wolff-Kishner reduction is used, without affecting the double bond.
Wolff-Kishner reagent It utilises hydrazine (NH2 − NH2) as the reducing agent in the presence of strong base JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEEin a high boiling protic solvent.
The driving force for the reaction is the conversion of hydrazine to nitrogen gas.
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.35. The product formed in the first step of the reaction of          (JEE Main 2021)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. a
Here, in first step only one mole of Mg/ Et2O attacks on bromine and form two 2MgBr in the first step.
On further moving in the reaction, two MgBr are eliminated to form alkene in respective positions.
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.36. What is the final product (major) 'A' in the given reaction ?          (JEE Main 2021)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. a
Steps involved in this reaction are as follows
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
Step 2 : Elimination reaction always give minor product than substitution reaction.
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.37. Identify products A and B.          (JEE Main 2021)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. b
In first step, KMnO4(dil.) help to break alkene in ketone and aldehyde and in second step, CrO3 is used for selective over oxidation of aldehyde only. CrO3 will form aldehyde to acid in product (B).
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.38. The dipole moments of CCl4, CHCl3 and CH4 are in the order    (2020)
(a) CHCl3 < CH4 = CCl4
(b) CCl4 < CH4 < CHCl3
(c) CH4 < CCl4 < CHCl3
(d) CH4 = CCl4 < CHCl3

Ans. d
Molecules having symmetrical geometry and identical side atoms have zero dipole moment, that is, the resultant dipole moment is zero. Whereas unsymmetrical molecules shows net dipole moment.
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.39. For the following reactions
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
Where

JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
ks and ke, are the rate constants for substitution and elimination respectively, and µ = ks/ke, the correct option is _______.    (2020)
(a)JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b)JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c)JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d)JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. b
The reaction involved is
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
Since, the nucleophile (A) is small so it will favor substitution rather than elimination product. Nucleophile (B) is bulkier, so it will favor elimination product. Thus, JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE and JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.40. The decreasing order of reactivity towards dehydrohalogenation (E1) reaction of the following compounds is    (2020)
(I) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(II) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(III) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(IV) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) (IV) > (II) > (III) > (I)
(b) (II) > (IV) > (I) > (III)
(c) (II) > (IV) > (III) > (I)
(d) (II) > (I) > (IV) > (III)

Ans. a
The strength of dehydrohalogenation depends upon the stability of alkene formed. More the stable alkene form, more the strength of dehydrohalogenation of the haloalkane.
(I)JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(II) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(III) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(IV) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
Since, the transition state of (IV) is more stable than (II), so, the alkene formed in (IV) is more stable than in (II). Thus, the correct decreasing order of dehydrohalogenation of the following compound is: (IV) > (II) > (III) > (I).


Q.41. Arrange the following bonds according to their average bond energies in descending order    (2020)
C – Cl, C – Br, C – F, C – I
(a) C – F > C – Cl > C – Br > C – I
(b) C – Br > C – I > C – Cl > C – F
(c) C – I > C – Br > C – Cl > C – F
(d) C – CI > C – Br > C – I > C – F

Ans. a
The bond enthalpy of C–X bond depends upon the size of the halogen X, as the size of the halogen increases, the bond energy decreases. Thus, the correct decreasing order of C–X, bond enthalpy is: C – F > C – Cl > C – Br > C – I.


Q.42. Which of these will produce the highest yield in Friedel Crafts reaction?   (2020)
(a)JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b)JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c)JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d)JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. c
The highest yield in Friedel Crafts reaction ins given by chlorobenzene. Since, phenol and aniline react with Lewis acid so reaction could not occur. –CONH2 group is a strong deactivating groups towards electrophilic aromatic subsitution reactions.


Q.43. X melts at low temperature and is a bad conductor of electricity in both liquid and solid state. X is    (2020)
(a) zinc sulphide
(b) mercury
(c) silicon carbide
(d) carbon tetrachloride

Ans. d
Since, CCl4 is a non-polar compound, so, it has low melting point and it is covalent compound, thus, it is bad conductor of electricity in both solid and liquid state.


Q.44. Which of the following reactions will not produce a racemic product?    (2020)
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. d
The reaction involved is
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.45. The major product of the following reaction is:    (2019)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. a
Mechanism involved for the given reaction is:
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.46. Which amongst the following is the strongest acid?    (2019)
(a) CHBr3
(b) CHI3
(c) CH(CN)3
(d) CHCl3

Ans. c
Due to the resonance stabilisation of the conjugate base, CH(CN)3 is the strongest acid amongst the given compounds.
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
The conjugate bases of CHBr3 and CHl3 are stabilised by inductive effect of halogens. This is why, they are less stable. Also, the conjugate base of CHCl3 involves back-bonding between 2p and 3p orbitals


Q.47. The major product of the following reaction is:    (2019)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. a
Dehydrohalogenation (β-elimination) occurs as:
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.48. Which hydrogen in compound (E) is easily replaceable during bromination reaction in presence of light?    (2019)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) α - hydrogen
(b) γ - hydrogen
(c) δ - hydrogen
(d) β - hydrogen

Ans. b
Allylic H is replaced due to the greater stability of allylic free radical.
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.49. The major product of the following reaction is:    (2019)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. b
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.50. The major product of the following reaction is:    (2019)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a)

 JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b)

 JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c)

 JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) 

JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. b
Heating of the given compound in presence of strong base is favoured for elimination reaction resulting in more stable alkene.
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.51. The major product of the following reaction is:    (2019)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. a
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.52. The major product of the following reaction is:    (2019)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. c
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.53. The major product of the following reaction is:    (2019)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. c
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.54. Increasing order of reactivity of the following compounds for SN1 substitution is:    (2019)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEEJEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) (B) < (C) < (D) < (A)
(b) (B) < (C) < (A) < (D)
(c) (B) < (A) < (D) < (C)
(d) (A) < (B) < (D) < (C)

Ans. c
In SN1 reaction carbocation acts as an intermediate.
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
Carbocation produced by (C) is more stable than carbocation produced by (D) due to + I effect of -OCH3 group.
Further in (A) there is formation of tertiary carbocation after rearrangement while (B) is primary carbocation.
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
So, the correct order is (C) > (D) > (A) > (B).


Q.55. Which of the following potential energy (PE) diagrams represents the SN1 reaction?    (2019)
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. a
The SN1 reaction energy diagram illustrates the dominant part of the substrate with respect to the reaction rate.
The rate determining step is the formation of the intermediate carbocation.
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.56. Increasing rate of SN1 reaction in the following compounds is:    (2019)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEEJEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) (A) < (B) < (C) < (4)
(b) (B) < (A) < (C) < (D)
(c) (B) < (A) < (D) < (3) 
(d) (A) < (B) < (D) < (C)

Ans. b
The rate of SN1 is decided by the stability of carbocation formed in the rate determining step.
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
Carbocation(D) is most stable due to +R effect of CH3O group, (C) is stabilised by +I and +H effects of the CH3 group; (B) is least stable due to -I effect of MeO group. So increasing order of rate of SN1 is (B) < (A) < (C) < (D)


Q.57. The major product of the following reaction is    (2019)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. c
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEEJEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.58. The major product ‘Y’ in the following reaction is:    (2019)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. c
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.59. Which one of the following is likely to give a precipitate with AgNO3 solution?    (2019)
(a) CH2 = CH —Cl
(b) CCI4
(c) CHCl3
(d) (CH3)3CCl

Ans. d
Carbocation is formed on reaction with Ag+
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE 
is most stable carbocation compared to other carbocations i.e.
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.60. Heating of 2-chloro-1-phenylbutane with EtOK/EtOH gives X as the major product. Reaction of X with Hg (OAc)2/H2O followed by NaBH4 gives Y as the major product. Y is:    (2019)
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. c
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.61. An ‘Assertion’ and a ‘Reason’ are given below. Choose the correct answer from the following options :
Assertion (A): Vinyl halides do not undergo nucleophilic substitution easily.
Reason (R): Even though the intermediate carbocation is stabilized by loosely held π-electrons, the cleavage is difficult because of strong bonding.    (2019)
(a) Both (A) and (R) are wrong statements.
(b) Both (A) and (R) are correct statements and (R) is the correct explanation of (A).
(c) Both (A) and (R) are correct statements but (R) is not the correct explanation of (A).
(d) (A) is a correct statement but (R) is a wrong statement.

Ans. d
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
Due to partial double bond character of C-halogen bond, halogen leaves with great difficulty, if at all it does. Hence, vinyl halides do not undergo nucleophilic substitution easily. So, assertion is correct.
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
Intermediate carbocation is not stabilised by loosely held-π electrons because empty orbital, being at 90°, cannot overlap with p-orbitals of π bond. So, reason is wrong.


Q.62. The major product of the following reaction is:    (2018)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. b
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.63. Which of the following will most readily give the dehydrohalogenation product?    (2018)
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. b
Carbanion formed after removal of hydrogen is resonance stabilised as it is adjacent to phenyl ring.


Q.64. The major product of the following reaction is:    (2018)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. c
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
Inversion takes place at the carbon containing bromine atom. 


Q.65. The increasing order of the reactivity of the following halides for the SN1 reaction is    (2017) 
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) (III) < (II) < (I) 
(b) (II) < (I) < (III) 
(c) (I) < (III) < (II) 
(d) (II) < (III) < (I) 

Ans. b
For any SN1 reaction, reactivity is decided by ease of dissociation of alkyl halide
R - X ⇌ R+ + X-
Higher the stability of R+ (carbocation) higher would be reactivity of SN1 reaction. Since the stability of cation follows the order.
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE 


Q.66. The major product obtained in the following reaction is    (2017)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) (±)C6H5CH(OtBu)CH2C6H5 
(b) C6H5CH = CHC6H5 
(c) (+)C6H5CH(OtBu)CH2C6H5 
(d) (-)C6H5CH(OtBu)CH2C6H5 

Ans. b
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.67. The major product of the following reaction is:    (2017)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(b) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(c) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(d) JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

Ans. a
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.68. The major product of the following reaction is:    (2017)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) CH3CH = CH – CH = CHCH3
(b) CH2 = CHCH = CHCH2CH3
(c) CH3CH = C = CHCH2CH3
(d) CH2 = CHCH2CH = CHCH3

Ans. a
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.69. 2-chloro-2-methylpentane on reaction with sodium methoxide in methanol yields:    (2016)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE 

JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(1) All of these 
(2) (a) and (c)
(3) (c) only
(4) (a) and (b) 

Ans. (1)
Strong nucleophile (OMe) polar solvent (MeOH) gives elimination products over substitution products but all products are possible in different yields.

JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE


Q.70. Which one of the following reagents is not suitable for the elimination reaction?    (2016)
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE
(a) NaI
(b) NaOH/H2O-EtOH
(c) NaOH/H2O
(d) NaOEt/EtOH

Ans. a
NaI gives Nucleophilic substitution reaction.
JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE 

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JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

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JEE Main Previous year questions (2016-22): Haloalkanes & Haloarenes - Notes | Study Chemistry for JEE - JEE

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