Hydrocarbons

28 JEE Main questions · Chemistry

ChemistryJEE Main 21 Jan 2026, Shift 1·Q3·MCQ·Moderate
Open
Alkene hydrogenation and oxidative cleavage
Identify A in the following reaction.
1. (1)
2. (2)
3. (3)
4. (4)
ChemistryJEE Main 21 Jan 2026, Shift 1·Q4·MCQ·Moderate
Open
Electrophilic addition to alkenes
A hydrocarbon ‘P' ( $\ce{C4H8}$ ) on reaction with HCl gives an optically active compound ‘Q' ( $\ce{C4H9Cl}$ ) which on reaction with one mole of ammonia gives compound ‘R' ( $\ce{C4H11N}$ ). ‘R' on diazotization followed by hydrolysis gives ‘S'. Identify P, Q, R and S.
1. (1)
2. (2)
3. (3)
4. (4)
We corrected a printing error in the original paper
Option (3): source printed R as “CH $_3$ –CH $_2$ =CH(NH $_2$ )–CH $_3$ ” (a pentavalent carbon); the “=” in the figure is corrected to the intended single bond “CH $_3$ –CH $_2$ –CH(NH $_2$ )–CH $_3$ ” (butan-2-amine).
ChemistryJEE Main 22 Jan 2026, Shift 1·Q11·MCQ·Easy–moderate
Open
Friedel crafts acylation of nitrobenzene
Given below are two statements :
Statement I : Benzene is nitrated to give nitrobenzene, which on further treatment with $\ce{CH3COCl}$ / $\ce{AlCl3}$ will give
Statement II : $\ce{NO2}$ group is a m-directing, and deactivating group.
In the light of the above statements, choose the most appropriate answer from the options given below.
1. (1)Statement I is correct but Statement II is incorrect.
2. (2)Both Statement I and Statement II are correct.
3. (3)Statement I is incorrect but Statement II is correct.
4. (4)Both Statement I and Statement II are incorrect.
We corrected a printing error in the original paper
Option (4): source printed “Both Statement I and Statement II is are incorrect”.
ChemistryJEE Main 22 Jan 2026, Shift 1·Q21·Numerical·Moderate
Open
Bromination and percentage of bromine
The cycloalkane (X) on bromination consumes one mole of bromine per mole of (X) and gives the product (Y) in which C:Br ratio is 3 : 1. The percentage of bromine in the product (Y) is %. (Nearest integer)
(Given : Molar mass in g mol $^{-1}$ H : 1, C : 12, O : 16, Br : 80 )
ChemistryJEE Main 22 Jan 2026, Shift 2·Q2·MCQ·Moderate
Open
Alkyne preparation and alkylation
Consider the following reaction :
The product Y formed is :
1. (1)2-methylhex-2-yne
2. (2)5-methylhex-2-yne
3. (3)2-methylhex-3-yne
4. (4)Isopropylbut-1-yne
ChemistryJEE Main 22 Jan 2026, Shift 2·Q20·MCQ·Moderate
Open
Alkyne formation and hydration
The dibromo compound [P] (molecular formula : $\ce{C9H10Br2}$ ) when heated with excess sodamide followed by treatment with dilute HCl gives [Q]. On warming [Q] with mercuric sulphate and dilute sulphuric acid yields [R] which gives positive Iodoform test but negative Tollen's test. The compound [P] is :
1. (1)
2. (2)
3. (3)
4. (4)
We corrected a printing error in the original paper
Source printed “dilute sulphuric acid yield [R]”.
ChemistryJEE Main 23 Jan 2026, Shift 1·Q10·MCQ·Easy–moderate
Open
Alkyne reduction geometrical isomers
But-2-yne and hydrogen (one mole each) are separately treated with (i) Pd/C and (ii) Na/liq. $\ce{NH3}$ to give the products X and Y respectively.
Identify the incorrect statements.
- (A)X and Y are stereoisomers.
- (B)Dipole moment of X is zero
- (C)Boiling point of X is higher than Y.
- (D)X and Y react with $\ce{O3}$ /Zn + $\ce{H2O}$ to give different products.
Choose the correct answer from the options given below :
1. (1)B and C only
2. (2)B and D only
3. (3)A and B only
4. (4)A and C only
ChemistryJEE Main 23 Jan 2026, Shift 1·Q12·MCQ·Easy–moderate
Open
Electrophilic substitution reactivity order
Consider the following compounds
Arrange these compounds in the increasing order of reactivity with nitrating mixture.
1. (1)c $<$ a $<$ b
2. (2)b $<$ c $<$ a
3. (3)c $<$ b $<$ a
4. (4)b $<$ a $<$ c
ChemistryJEE Main 23 Jan 2026, Shift 2·Q10·MCQ·Moderate
Open
Hbr addition with hydride shift
Identify (P)
1. (1)
2. (2)
3. (3)
4. (4)
ChemistryJEE Main 24 Jan 2026, Shift 1·Q3·MCQ·Easy–moderate
Open
Alkene stability hyperconjugation
Arrange the following alkenes in decreasing order of stability.
Choose the correct answer from the options given below :
1. (1)III $>$ I $>$ II $>$ IV
2. (2)III $>$ II $>$ I $>$ IV
3. (3)I $>$ III $>$ II $>$ IV
4. (4)I $>$ III $>$ IV $>$ II
ChemistryJEE Main 24 Jan 2026, Shift 2·Q20·MCQ·Easy–moderate
Open
Conformations of n-butane
Given below are two statements :
Statement I : There are several conformers for n-butane. Out of those conformers,
is the least stable and most stable conformer is
Statement II : As the dihedral angle increases, torsional strain decreases from (X) to (Y).
In the light of the above statements, choose the correct answer from the options given below :
1. (1)Both Statement I and Statement II are false
2. (2)Statement I is false but Statement II is true
3. (3)Statement I is true but Statement II is false
4. (4)Both Statement I and Statement II are true
ChemistryJEE Main 28 Jan 2026, Shift 1·Q8·MCQ·Moderate
Open
Alkyne preparation and reactions
Given below are two statements for the following reaction sequence.
Statement I: Compound ‘Z' will give yellow precipitate with NaOI.
Statement II: Compound ‘Q' has two different types of ‘H' atoms (aromatic : aliphatic) in the ratio 1 : 3.
In the light of the above statements, choose the correct answer from the option given below:
1. (1)Statement I is true but Statement II is false
2. (2)Both Statement I and Statement II are true
3. (3)Statement I is false but Statement II is true
4. (4)Both Statement I and Statement II are false
ChemistryJEE Main 28 Jan 2026, Shift 1·Q15·MCQ·Easy–moderate
Open
Peroxide effect anti-markovnikov addition
$\ce{Ph-CH=CH2 ->[(PhCOO)2][HBr] Product}$
Consider the above reaction
- (A)The reaction proceeds through a more stable radical intermediate.
- (B)The role of peroxide is to generate $\dot{\mathrm{H}}$ (Hydrogen radical).
- (C)During this reaction, benzene is formed as a by-product.
- (D)1-Bromo-2-phenylethane is formed as the minor product.
- (E)The same reaction in absence of peroxide proceeds via carbocation intermediate.
Identify the correct statements. Choose the correct answer from the options given below:
1. (1)A & E Only
2. (2)A, B & D Only
3. (3)C, D & E Only
4. (4)A, C & E Only
We corrected a printing error in the original paper
Source printed “benzene is formed as a biproduct” and “1-Bromo-2-phenylethane is fanned as the minor product”.
ChemistryJEE Main 28 Jan 2026, Shift 2·Q1·MCQ·Easy
Open
Nitro group effect on ring
Identify the correct statements :
The presence of – $\ce{NO2}$ group in benzene ring
- (A)activates the ring towards electrophilic substitutions.
- (B)deactivates the ring towards electrophilic substitutions.
- (C)activates the ring towards nucleophilic substitutions.
- (D)deactivates the ring towards nucleophilic substitutions.
1. (1)B and D Only
2. (2)C and A Only
3. (3)A and D Only
4. (4)B and C Only
ChemistryJEE Main 28 Jan 2026, Shift 2·Q6·MCQ·Easy–moderate
Open
Controlled oxidation of alkanes
The reactions which produce alcohol as the product are :
- (A) $\ce{CH4 + O2}\xrightarrow[\Delta]{\ce{Mo2O3}}$
- (B) $\ce{2CH3CH3 + 3O2}\xrightarrow[\Delta]{\ce{(CH3COO)2Mn}}$
- (C) $\ce{(CH3)3CH}\xrightarrow{\ce{KMnO4}}$
- (D) $\ce{2CH4 + O2}\xrightarrow{\mathrm{Cu}/523\,\mathrm{K}/100\,\mathrm{atm.}}$
- (E) $\ce{CH3-CH=CH-CH3}\xrightarrow{\ce{KMnO4}/\ce{H+}}$
Choose the correct answer from the options given below :
1. (1)A and D Only
2. (2)A, C and E Only
3. (3)C and D Only
4. (4)B, D and E Only
We corrected a printing error in the original paper
Source printed “the product area”.
ChemistryJEE Main 2 Apr 2026, Shift 1·Q16·MCQ·Moderate
Open
Directive influence in electrophilic substitution
For the given molecule, “x”, the preferred site for the attack of the electrophile is :
1. (1)Predominantly at “r”
2. (2)“r” and “u”
3. (3)“p” and “s”
4. (4)Predominantly at “u”
ChemistryJEE Main 2 Apr 2026, Shift 1·Q22·Numerical·Moderate
Open
Monochlorination of cycloalkane isomers
Consider the isomers of hydrocarbon with molecular formula $\ce{C5H10}$ . These isomers do not decolourise $\ce{KMnO4}$ solution. These isomers are subjected to chlorination with chlorine in presence of light to give monochloro compounds. The total number of monochloro compounds (structural isomers only) formed is .
ChemistryJEE Main 2 Apr 2026, Shift 1·Q23·Numerical·Easy–moderate
Open
Alkane combustion stoichiometry
One mole of an alkane (x) requires 8 mole oxygen for complete combustion. Sum of number of carbon and hydrogen atoms in the alkane (x) is .
ChemistryJEE Main 2 Apr 2026, Shift 2·Q14·MCQ·Easy–moderate
Open
Alkane isomerisation aromatisation and cyclisation
The compound (X) on
- (i)on heating in the presence of anhydrous $\ce{AlCl3}$ and HCl gas gives 2, 4–dimethyl pentane
- (ii)aromatization gives toluene and
- (iii)cyclisation gives methyl cyclohexane
The correct name of compound (X) is :
1. (1)Hept-2-ene
2. (2)Hept-1,3,5-triene
3. (3)Heptane
4. (4)Hept-2,4,6-triene
ChemistryJEE Main 4 Apr 2026, Shift 1·Q14·MCQ·Moderate
Open
Ozonolysis of alkenes
An alkene (X) on ozonolysis followed by reduction gives following products.
The alkene (X) is :
1. (1)
2. (2)
3. (3)
4. (4)
ChemistryJEE Main 4 Apr 2026, Shift 2·Q14·MCQ·Moderate
Open
Alkyne preparation and reduction
Compound (X) is subjected to the sequence of reactions as shown above. Molar mass of the major product (Y) formed is g mol $^{-1}$ .
(Given molar mass in g mol $^{-1}$ C : 12, H : 1, O : 16)
1. (1)90
2. (2)118
3. (3)160
4. (4)125
ChemistryJEE Main 5 Apr 2026, Shift 1·Q15·MCQ·Easy–moderate
Open
Friedel crafts alkylation
For the following Friedel Craft's alkylation reaction, which of the statements are correct ?
- (A)Major product is n-propyl benzene.
- (B)iso-propyl carbocation intermediate is also generated
- (C)Multiple substitution is inevitable.
- (D)Introducing electron-donating substituent on benzene will not produce any alkylbenzene.
Choose the correct answer from the options given below :
1. (1)A and D only
2. (2)B and C only
3. (3)A and C only
4. (4)B and D only
ChemistryJEE Main 5 Apr 2026, Shift 2·Q13·MCQ·Easy–moderate
Open
Relative stability of alkenes
IUPAC names of some alkenes are given below :
Find out the correct stability order.
- (A)2-Methylbut-2-ene
- (B)cis-But-2-ene
- (C)2,3-Dimethylbut-2-ene
- (D)Prop-1-ene
Choose the correct answer from the options given below :
1. (1)C $>$ A $>$ B $>$ D
2. (2)C $>$ A $>$ D $>$ B
3. (3)B $>$ D $>$ A $>$ C
4. (4)A $>$ B $>$ C $>$ D
We corrected a printing error in the original paper
Source printed “IUPAC name of the some alkenes are given below”.
ChemistryJEE Main 6 Apr 2026, Shift 1·Q15·MCQ·Easy–moderate
Open
Preparation of alkanes
Given below are two statements :
Statement-I : Methane can be prepared by decarboxylation of sodium ethanoate, Kolbe's electrolysis of sodium acetate and reaction of $\ce{CH3MgBr}$ with water.
Statement-II : Methane cannot be prepared from unsaturated hydrocarbons and by Wurtz reaction.
In the light of the above statements, choose the correct answer from the options given below.
1. (1)Both Statement-I and Statement-II are true.
2. (2)Both Statement-I and Statement-II are false.
3. (3)Statement-I is true but Statement-II is false.
4. (4)Statement-I is false but Statement-II is true.
ChemistryJEE Main 6 Apr 2026, Shift 2·Q15·MCQ·Moderate
Open
Elimination and alkyne hydration
An optically active alkyl bromide $\ce{C4H9Br}$ , reacts with ethanolic KOH to form major compound [A] which reacts with bromine to give compound [B]. Compound [B] reacts with ethanolic KOH and sodamide to give compound [C]. One molecule of water adds to compound [C] on warming with mercuric sulphate and dilute sulphuric acid at 333 K to form compound [D]. The functional group in compound D will be confirmed by:
1. (1)Haloform test
2. (2)Lucas test
3. (3)Silver mirror test
4. (4)Benedict test
ChemistryJEE Main 6 Apr 2026, Shift 2·Q19·MCQ·Moderate
Open
Aromatisation and friedel crafts acylation
Consider the following reactions. Total number of electrons in the $\pi$ bonds and lone pair of electrons in the product (X) is:
1. (1)12
2. (2)16
3. (3)14
4. (4)18
ChemistryJEE Main 6 Apr 2026, Shift 2·Q22·Numerical·Easy–moderate
Open
Alkane combustion and free radical chlorination
An alkane (Y) requires 8 moles of oxygen for complete combustion and on chlorination with $\ce{Cl2}$ /h $\nu$ , (Y) gives only one monochlorinated product (Z). The total number of primary carbon atoms in (Y) is .
We corrected a printing error in the original paper
Source printed “ $\ce{Cl2}$ /hv” (Latin v for $\nu$ ).
ChemistryJEE Main 8 Apr 2026, Shift 2·Q15·MCQ·Moderate
Open
Free radical chlorination of alkanes
n-Butane on monochlorination under photochemical conditions gives an optically active compound “P”. “P” on further chlorination gives dichloro compounds.
The number of dichloro compounds obtained (ignore stereoisomers) is :
1. (1)3
2. (2)4
3. (3)5
4. (4)6