Treatment of buta-1,3-diyne with (2 equivalents), followed by reaction with excess of gives X as the major product. The maximum number of carbon atoms that are collinear (in a straight line) in X is ____.
Hydrocarbons — JEE Previous Year Questions
Every Hydrocarbons question asked in JEE Main and JEE Advanced across the last 186 papers — 191 questions, each with its correct answer. Free to read, no account needed.
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An alkane requires 8 moles of oxygen for complete combustion and on chlorination with /, gives only one monochlorinated product . The total number of primary carbon atoms in is __________.
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 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
- (A)Both Statement I and Statement II are true
- (B)Both Statement I and Statement II are false
- (C)Statement I is true but Statement II is false
- (D)Statement I is false but Statement II is true
"P" is a hydrocarbon of molecular formula: CH. On ozonolysis, "P" forms "Q". "Q" on treatment with alkali under reflux condition produces "R", which on treatment with I/NaOH gives a yellow precipitate. Acidification of the solution gives "S". The structure of "S" is given below:
The correct structure of "P" is
- (A)(1)
- (B)(2)
- (C)(3)
- (D)(4)
Identify the correct IUPAC name of hydrocarbon (x) containing three primary carbon atoms and with molar mass 72 g mol⁻¹.
- (A)1,1-Dimethylcyclopropane
- (B)2,2-Dimethylpropane
- (C)2-Methylbutane
- (D)n-pentane
IUPAC name of the 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 :
- (A)C > A > B > D
- (B)C > A > D > B
- (C)B > D > A > C
- (D)A > B > C > D
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 alkyl benzene.
Choose the correct answer from the options given below:
- (A)A and D only
- (B)B and C only
- (C)A and C only
- (D)B and D only
Compound (X) [styrene] is subjected to the sequence of reactions as shown above: (i) (ii) excess (iii) (iv) , (l), giving Major Product (Y). Molar mass of the major product (Y) formed is ______ g mol.
(Given molar mass in g mol C:12, H: 1, O: 16)
- (A)90
- (B)118
- (C)160
- (D)125
Consider the following sequence of reactions to give the major product
g of the major product formed is reacted with solution to liberate a gas which occupied 11.2 at STP. _______ g. (Given molar mass in g H:1, C:12, O:16, Cl:35.5)
The compound (X) on
(i) on heating in the presence of anhydrous 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:
- (A)Hept-2-ene
- (B)Hept-1,3,5-triene
- (C)Heptane
- (D)Hept-2,4,6-triene
Consider the isomers of hydrocarbon with molecular formula . These isomers do not decolourise 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 ________.
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 ________.
PhCHCH Product
Consider the above reaction
A. The reaction proceeds through a more stable radical intermediate.
B. The role of peroxide is to generate (Hydrogen radical).
C. During this reaction, benzene is formed as a biproduct.
D. 1-Bromo-2-phenylethane is fanned 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:
- (A)A & E Only
- (B)A, B & D Only
- (C)C, D & E Only
- (D)A, C & E Only
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:
- (A)Statement I is true but Statement II is false
- (B)Both Statement I and Statement II are true
- (C)Statement I is false but Statement II is true
- (D)Both Statement I and Statement II are false
Identify the correct statements :
The presence of 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.
- (A)B and D Only
- (B)C and A Only
- (C)A and D Only
- (D)B and C Only
Given below are two statements :
Statement I : There are several conformers for n-butane. Out of those conformers, (X) is the least stable and most stable conformer is (Y)
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 :
- (A)Both Statement I and Statement II are false
- (B)Statement I is false but Statement II is true
- (C)Statement I is true but Statement II is false
- (D)Both Statement I and Statement II are true
Identify (P)
- (A)(1)
- (B)(2)
- (C)(3)
- (D)(4)
But-2-yne and hydrogen (one mole each) are separately treated with (i) Pd/C and (ii) Na/liq. NH 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 O/Zn + HO to give different products.
Choose the correct answer from the options given below :
- (A)B and C only
- (B)B and D only
- (C)A and B only
- (D)A and C only
Consider the following compounds
Arrange these compounds in the increasing order of reactivity with nitrating mixture.
- (A)c < a < b
- (B)b < c < a
- (C)c < b < a
- (D)b < a < c
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 H : 1, C : 12, O : 16, Br : 80 )
Consider the following reaction :
The product Y formed is :
- (A)2-methylhex-2-yne
- (B)5-methylhex-2-yne
- (C)2-methylhex-3-yne
- (D)Isopropylbut-1-yne
The dibromo compound [P] (molecular formula : ) when heated with excess sodamide followed by treatment with dilute HCl gives [Q]. On warming [Q] with mercuric sulphate and dilute sulphuric acid yield [R] which gives positive Iodoform test but negative Tollen's test. The compound [P] is :
- (A)(1)
- (B)(2)
- (C)(3)
- (D)(4)
Given below are two statements :
Statement I : Benzene is nitrated to give nitrobenzene, which on further treatment with CHCOCl / AlCl will give
Statement II : NO 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.
- (A)Statement I is correct but Statement II is incorrect.
- (B)Both Statement I and Statement II are correct.
- (C)Statement I is incorrect but Statement II is correct.
- (D)Both Statement I and Statement II is are incorrect.
Identify A in the following reaction.
- (A)(1)
- (B)(2)
- (C)(3)
- (D)(4)
1,2-dibromocyclooctane (Major product). 'P' is:
- (A)(1)
- (B)(2)
- (C)(3)
- (D)(4)
Choose the correct set of reagents for the following conversion: Ethyl benzene (product shown in figure)
- (A); ; alc. KOH
- (B); anhy.; aq. KOH
- (C)anhy.; ; aq. KOH
- (D)anhy.; ; alc. KOH
The reactions which cannot be applied to prepare an alkene by elimination, are: A. Bromocyclohexane B. C. D. Phenol E. . Choose the correct answer from the option given below:
- (A)B & E Only
- (B)B, C & D Only
- (C)A, C & D Only
- (D)B & D Only
Given below are two statements:
Statement I: Ozonolysis followed by treatment with Zn, HO of cis-2-butene gives ethanal.
Statement II: The production obtained by ozonolysis followed by treatment with Zn, HO of 3,6-dimethyloct-4-ene has no chiral carbon atom.
In the light of the above statements, choose the correct answer from the options given below.
- (A)Both Statement I and Statement II are true
- (B)Statement I is false but Statement II is true
- (C)Statement I is true but Statement II is false
- (D)Both Statement I and Statement II are false
The number of optically active products obtained from the complete ozonolysis of the given compound is:
- (A)2
- (B)0
- (C)1
- (D)4
Benzene is treated with oleum to produce compound (X) which when further heated with molten sodium hydroxide followed by acidification produces compound (Y). The compound Y is treated with zinc metal to produce compound (Z). Identify the structure of compound (Z) from the following option.
- (A)(1)
- (B)(2)
- (C)(3)
- (D)(4)
Predict the major product when methylcyclohexane is subjected to the following reagents in sequence: (1) Br/h; (2) Alcoholic/KOH, ; (3) HBr/ROOR, h.
- (A)(1)
- (B)(2)
- (C)(3)
- (D)(4)
Which compound (shown in the figure) would give 3-methyl-6-oxoheptanal upon ozonolysis? Choose the correct option:
- (A)(1)
- (B)(2)
- (C)(3)
- (D)(4)
Given below are two statements: Statement (I): Neopentane forms only one monosubstituted derivative. Statement (II): Melting point of neopentane is higher than n-pentane. In the light of the above statements, choose the most appropriate answer from the options given below:
- (A)Statement I is correct but Statement II is incorrect
- (B)Both Statement I and Statement II are correct
- (C)Both Statement I and Statement II are incorrect
- (D)Statement I is incorrect but Statement II is correct
Isomeric hydrocarbons → negative Baeyer’s test (Molecular formula ). The total number of isomers from above with four different non-aliphatic substitution sites is ______.
Given below are two statements: Statement (I): On nitration of m-xylene with , followed by oxidation, 4-nitrobenzene-1,3-dicarboxylic acid is obtained as the major product. Statement (II): group is o/p-directing while group is m-directing group. In the light of the above statements, choose the correct answer from the options given below:
- (A)Both Statement I and Statement II are false
- (B)Statement I is false but Statement II is true
- (C)Both Statement I and Statement II are true
- (D)Statement I is true but Statement II is false
The total number of compounds from below (shown in the figure) when treated with hot KMnO giving benzoic acid is:
- (A)3
- (B)4
- (C)6
- (D)5
Identify product [A], [B] and [C] in the following reaction sequence: CH-CCH [A] [B] + [C]
- (A)[A]: , [B]: , [C]:
- (B)[A]: , [B]: , [C]:
- (C)[A]: , [B]: , [C]:
- (D)[A]: , [B]: , [C]:
Aman has been asked to synthesise the molecule (x) shown in the figure. He thought of preparing the molecule using an aldol condensation reaction. He found a few cyclic alkenes in his laboratory. He thought of performing ozonolysis reaction on alkene to produce a dicarbonyl compound followed by aldol reaction to prepare "x". Predict the suitable alkene that can lead to the formation of "x".
- (A)(1)
- (B)(2)
- (C)(3)
- (D)(4)
Following are the four molecules "P", "Q", "R" and "S" (shown in the figure). Which one among the four molecules will react with H-Br(aq) at the fastest rate ?
- (A)S
- (B)Q
- (C)R
- (D)P
Propane molecule on chlorination under photochemical condition gives two di-chloro products, "x" and "y". Amongst "x" and "y", "x" is an optically active molecule. How many tri-chloro products (consider only structural isomers) will be obtained from "x" when it is further treated with chlorine under the photochemical condition?
- (A)4
- (B)2
- (C)5
- (D)3
Match List-I (Isomers of ) with List-II (Ozonolysis product). Choose the correct answer from the options given below:
| List-I (Isomers of $C_{10}H_{14}$) | List-II (Ozonolysis product) |
|---|---|
| A.see figure | I.see figure |
| B.see figure | II.see figure |
| C.see figure | III.see figure |
| D.see figure | IV.see figure |
- (A)(A)-(II), (B)-(III), (C)-(I), (D)-(IV)
- (B)(A)-(III), (B)-(IV), (C)-(I), (D)-(II)
- (C)(A)-(III), (B)-(II), (C)-(I), (D)-(IV)
- (D)(A)-(I), (B)-(IV), (C)-(III), (D)-(II)
A compound 'X' absorbs 2 moles of hydrogen and 'X' upon oxidation with gives , and . The total number of bonds present in the compound 'X' is __________.
When sec-butylcyclohexane reacts with bromine in the presence of sunlight, the major product is:
- (A)(1)
- (B)(2)
- (C)(3)
- (D)(4)
The alkane from below having two secondary hydrogens is:
- (A)4-Ethyl-3,4-dimethyloctane
- (B)2,2,4,4-Tetramethylhexane
- (C)2,2,3,3-Tetramethylpentane
- (D)2,2,4,5-Tetramethylheptane
The compound with molecular formula , which gives only one monobromo derivative and takes up four moles of hydrogen per mole for complete hydrogenation has ______ electrons.
Given below are two statements.
Statement I: One mole of propyne reacts with excess of sodium to liberate half a mole of H₂ gas.
Statement II: Four grams of propyne reacts with NaNH₂ to liberate NH₃ gas which occupies 224 mL at STP.
In the light of the above statements, choose the most appropriate answer:
- (A)Statement I is correct but Statement II is incorrect
- (B)Both Statement I and Statement II are correct
- (C)Statement I is incorrect but Statement II is correct
- (D)Both Statement I and Statement II are incorrect
Identify the INCORRECT statements regarding geometrical isomerism: (A) Propene shows geometrical isomerism. (B) The trans isomer has identical atoms/groups on the opposite sides of the double bond. (C) cis-but-2-ene has a higher dipole moment than trans-but-2-ene. (D) 2-methylbut-2-ene shows two geometrical isomers. (E) The trans isomer has a lower melting point than the cis isomer. Choose the correct answer:
- (A)(A), (D) and (E) only
- (B)(C), (D) and (E) only
- (C)(B) and (E) only
- (D)(A) and (D) only
In the following reaction sequence, the major product Q is
L − Glucose P Q
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
In the following sequence of reactions, benzene reacts with succinic anhydride in presence of to give A, which on treatment with Zn-Hg/HCl gives B, which on treatment with Conc. gives C. What is the structure of C ?
- (A)(1)
- (B)(2)
- (C)(3)
- (D)(4)
The incorrect statement regarding ethyne is:
- (A)The C-C bond in ethyne is shorter than that in ethene
- (B)Both carbons are sp hybridised
- (C)Ethyne is linear
- (D)The carbon-carbon bond in ethyne is weaker than that in ethene
Number of compounds from the following which cannot undergo Friedel-Crafts reactions is _______: toluene, nitrobenzene, xylene, cumene, aniline, chlorobenzene, m-nitroaniline, m-dinitrobenzene.
Identify the product A and product B in the following set of reactions. Propene () undergoes (i) to give major product A, and (ii) hydroboration-oxidation with then to give major product B.
- (A)A-, B-
- (B)A-, B-
- (C)A-, B-
- (D)A-, B-
Identify major product "X" formed in the following reaction:
(Major product)
- (A)(1)
- (B)(2)
- (C)(3)
- (D)(4)
The major product of the following reaction is P: on treatment with (i) Na/liq. then (ii) dil. at 273 K gives 'P'. The number of oxygen atoms present in product 'P' is _______ (nearest integer).
When cyclohexene is treated with – and heated, the product "A" is:
- (A)picric acid
- (B)oxalic acid
- (C)acetic acid
- (D)adipic acid
Given below are two statements:
Statement I: Nitration of benzene involves the following step: .
Statement II: Use of a Lewis base promotes the electrophilic substitution of benzene.
In the light of the above statements, choose the most appropriate answer from the options given below:
- (A)Both Statement I and Statement II are incorrect
- (B)Statement I is correct but Statement II is incorrect
- (C)Both Statement I and Statement II are correct
- (D)Statement I is incorrect but Statement II is correct
Given below are two statements:
Assertion (A): The cis form of an alkene is found to be more polar than the trans form.
Reason (R): The dipole moment of the trans isomer of 2-butene is zero.
In the light of the above statements, choose the correct answer from the options given below:
- (A)Both (A) and (R) are true but (R) is not the correct explanation of (A)
- (B)(A) is true but (R) is false
- (C)Both (A) and (R) are true and (R) is the correct explanation of (A)
- (D)(A) is false but (R) is true
on treatment with NaOH in gives product 'A'. 'A' with gives product 'B', and 'A' with diborane followed by gives product 'C'. Identify product B and product C:
- (A)B = C = 2-Propanol
- (B)B = 2-Propanol, C = 1-Propanol
- (C)B = 1-Propanol, C = 2-Propanol
- (D)B = C = 1-Propanol
. Acid D formed in above reaction is:
- (A)Gluconic acid
- (B)Succinic acid
- (C)Oxalic acid
- (D)Malonic acid
Match List-I (Haloalkane / freon) with List-II (Industrial use). Choose the correct answer from the options given below:
| List-I (Compound) | List-II (Use) |
|---|---|
| A.Carbon tetrachloride | I.Paint remover |
| B.Methylene chloride | II.Refrigerators and air conditioners |
| C.DDT | III.Fire extinguisher |
| D.Freons | IV.Non Biodegradable insecticide |
- (A)(A)-(I), (B), (II), (C)-(III), (D)-(IV)
- (B)(A)-(III), (B)-(I), (C)-(IV), (D)-(II)
- (C)(A)-(IV), (B)-(III), (C)-(II), (D)-(I)
- (D)(A)-(II), (B)-(III), (C)-(I), (D)-(IV)
Total number of isomeric compounds (including stereoisomers) formed by monochlorination of 2-methylbutane is __________.
In the given reactions identify A and B. (cis-pent-2-ene structure); "B".
- (A)A: 2-Pentyne, B: trans-2-butene
- (B)A: n-Pentane, B: trans-2-butene
- (C)A: 2-Pentyne, B: Cis-2-butene
- (D)A: n-Pentane, B: Cis-2-butene
Which among the following has highest boiling point?
- (A)
- (B)
- (C)
- (D)
Number of alkanes obtained on electrolysis of a mixture of and is ______.
Major product of the following reaction is (shown in the figure).
- (A)(1)
- (B)(2)
- (C)(3)
- (D)(4)
Compound A formed in the following reaction reacts with B gives the product C. Find out A and B.
- (A)A , B
- (B)A , B
- (C)A , B
- (D)A , B
Consider the given reaction . The total number of oxygen atoms present per molecule of the product (P) is ______ .
Identify product A and product B :
- (A)(1)
- (B)(2)
- (C)(3)
- (D)(4)
The correct statement regarding nucleophilic substitution reaction in a chiral alkyl halide is:
- (A)Retention occurs in reaction and inversion occurs in reaction.
- (B)Racemisation occurs in reaction and retention occurs in reaction.
- (C)Racemisation occurs in both and reactions.
- (D)Racemisation occurs in reaction and inversion occurs in reaction.
3-Methylhex-2-ene on reaction with HBr in presence of peroxide forms an addition product (A). The number of possible stereoisomers for 'A' is __________.
Major product formed in the following reaction is a mixture of :
- (A)(1)
- (B)(2)
- (C)(3)
- (D)(4)
The product formed in the following multistep reaction is: with i) ii) iii) PCC iv)
- (A)
- (B)
- (C)
- (D)
The major product formed in the Friedel-Craft acylation of chlorobenzene is.
- (A)(1)
- (B)(2)
- (C)(3)
- (D)(4)
In the above reaction, the left hand side and right hand side rings are named as and respectively. They undergo ring expansion. The correct statement for this reaction is:
- (A)Finally both rings will become six membered each
- (B)Finally both rings will become five membered each
- (C)Only will become membered
- (D)Ring expansion can go upto seven membered rings
For the given reaction . The total number of possible products formed by tertiary carbocation of A is _____.
In the following reaction is:
(major product)
- (A)
- (B)
- (C)
- (D)cyclohexane
-hexene Products. The two products formed in above reaction are:
- (A)Butanoic acid and acetic acid
- (B)Butanal and acetic acid
- (C)Butanal and acetaldehyde
- (D)Butanoic acid and acetaldehyde
The major product 'P' formed in the reaction given in the figure is:
- (A)(1)
- (B)(2)
- (C)(3)
- (D)(4)
The major product 'P' formed in the given reaction is
- (A)(1)
- (B)(2)
- (C)(3)
- (D)(4)
Molar mass of the hydrocarbon (X) which on ozonolysis consumes one mole of per mole of (X) and gives one mole each of ethanal and propanone is _______ g (Molar mass of C : 12 g , H : 1 g )
Number of bromo derivatives obtained on treating ethane with excess of in diffused sunlight is _____.
But-2-yne is reacted separately with one mole of hydrogen to give A (using Na in liquid ) and B (using ). (A) A is more soluble than B. (B) The boiling point and melting point of A are higher and lower than B respectively. (C) A is more polar than B because dipole moment of A is zero. (D) adds easily to B than A. Identify the incorrect statements from the options given below:
- (A)B, C and D only
- (B)A and B only
- (C)A, C and D only
- (D)B and C only
'X' in the given reaction is:
- (A)(1)
- (B)(2)
- (C)(3)
- (D)(4)
When a hydrocarbon A undergoes complete combustion it requires 11 equivalents of oxygen and produces 4 equivalents of water. What is the molecular formula of A?
- (A)
- (B)
- (C)
- (D)
Choose the correct set of reagents for the following conversion.
trans-() cis-()
- (A), aq. KOH, , Na(Liq)
- (B), alc. KOH, , Lindlar Catalyst
- (C), aq. KOH, , Lindlar Catalyst
- (D), alc. KOH, , Na(Liq)
A hydrocarbon 'X' with formula uses two moles on catalytic hydrogenation of its one mole. On ozonolysis, 'X' yields two moles of methane dicarbaldehyde. The hydrocarbon 'X' is:
- (A)cyclohexa-1,4-diene
- (B)cyclohexa-1,3-diene
- (C)1-methylcyclopenta-1,4-diene
- (D)hexa-1,3,5-triene
The major products 'A' and 'B', respectively formed when the alkene shown reacts with cold dilute (giving A) and with at (giving B), are
- (A)(1)
- (B)(2)
- (C)(3)
- (D)(4)
17 mg of a hydrocarbon (M.F. CH) takes up 8.40 mL of the H gas measured at 0 °C and 760 mm of Hg. Ozonolysis of the same hydrocarbon yields the products shown. The number of double bond/s present in the hydrocarbon is ________ .
Find out the major product for the following reaction.
- (A)(1)
- (B)(2)
- (C)(3)
- (D)(4)
When a hydrocarbon A undergoes combustion in the presence of air, it requires equivalents of oxygen and produces equivalents of water. What is the molecular formula of A?
- (A)
- (B)
- (C)
- (D)
Find out the major products from the following reaction
- (A)(1)
- (B)(2)
- (C)(3)
- (D)(4)
Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: Benzene is more stable than hypothetical cyclohexatriene.
Reason R: The delocalized electron cloud is attracted more strongly by nuclei of carbon atoms.
In the light of the above statements, choose the correct answer from the options given below:
- (A)Both A and R are correct and R is the correct explanation of A
- (B)Both A and R are correct but R is NOT the correct explanation of A
- (C)A is false but R is true
- (D)A is true but R is false
Maximum number of isomeric monochloro derivatives which can be obtained from -tetramethylhexane by chlorination is _________
The number of (methylene) groups in the product formed from the following reaction sequence is____.
If the reaction sequence given below is carried out with 15 moles of acetylene, the amount of the product formed (in g) is ________.
The yields of , , and are given in parentheses.
[Given: Atomic mass of H = 1, C = 12, O = 16, Cl = 35]
The number of isomeric tetraenes (NOT containing -hybridized carbon atoms) that can be formed from the following reaction sequence is____.
In bromination of Propyne, with Bromine 1, 1, 2, 2-tetrabromopropane is obtained in 27% yield. The amount of 1, 1, 2, 2 tetrabromopropane obtained from 1 g of Bromine in this reaction is ______ × g. (Nearest integer)
(Molar Mass : Bromine = 80 g/mol)
When enthanol is heated with conc. HSO, a gas is produced. The compound formed, when this gas is treated with cold dilute aqueous solution of Baeyer's reagent, is :
- (A)Formaldehyde
- (B)Formic acid
- (C)Glycol
- (D)Ethanoic acid
Which among the following pairs of the structures will give different products on ozonolysis? (Consider the double bonds in the structures are rigid and not delocalized.)
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
Arrange the following in increasing order of reactivity towards nitration
A. p-xylene
B. bromobenzene
C. mesitylene
D, nitrobenzene
E. benzene
Choose the correct answer from the options given below
- (A)
- (B)
- (C)
- (D)
The major product of the following reaction is
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
In the presence of sunlight, benzene reacts with Cl to give product, X. The number of hydrogens in X is__________.
Total number of isomers (including stereoisomers) obtain on monochlorination of methylcyclohexane is ________.
A compound 'A' on reaction with 'X' and 'Y' produces the same major product but different by product 'a' and 'b'. Oxidation of 'a’ gives a substance produced by ants.
‘X’ and ‘Y’ respectively are :
- (A) and dil. , 273 K
- (B),(dilute), 273 K and
- (C) and ,
- (D), and
Two isomers 'A' and 'B' with molecular formula give different products on oxidation with in acidic medium. Isomer 'A' on reaction with results in effervescence of a gas and gives ketone. The compound 'A' is
- (A)But-1-ene
- (B)cis-But-2-ene
- (C)trans-But-2ene
- (D)2-methyl propene
The stable carbocation formed in the above reaction is :
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
The major product of the following reaction contains ______ bromine atom(s).
The major product (P) in the reaction
[Ph is – ] is
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
'A' and 'B' respectively are:
A Ethane-1,2-dicarbaldehyde + Glyoxal/Oxaldehyde
B 5-oxohexanal
- (A)1-methylcyclohex-1, 3-diene & cyclopentene
- (B)Cyclohex-1, 3-diene & cyclopentene
- (C)1-methylcyclohex-1,4-diene & 1-methylcyclopent-1-ene
- (D)Cyclohex-1,3-diene & 1-methylcyclopent-1-ene
What will be the major product of following sequence of reactions?
Printed reaction scheme (words and formulae only): n – Bu– ; above the arrow: (i) n – BuLi, n – CHCl ; below the arrow: (ii) Lindlar cat, H
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
Halogenation of which one of the following will yield m-substituted product with respect to methyl group as a major product?
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
The products formed in the following reaction.
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
Number of grams of bromine that will completely react with 5.0g of pent-1-ene is _______ × g. (Atomic mass of Br = 80 g/mol) [Nearest Integer)
In the following structures, which one is having staggered conformation with maximum dihedral angle?
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
In the given reactions sequence, the major product 'C' is :
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
Given below are two statements.
Statement I : The presence of weaker - 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.
The major product 'A' of the following given reaction has _____ sp hybridized carbon atoms.
2,7 - Dimethyl1 - 2, 6 - octadiene A (Mojor Product)
The major product formed in the following reaction is
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
The reaction sequence(s) that would lead to -xylene as the major product is (are)
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
The amount of energy required to break a bond is same as the amount of energy released when the same bond is formed. In gaseous state, the energy required for homolytic cleavage of a bond is called Bond Dissociation Energy (BDE) or Bond Strength. BDE is affected by s-character of the bond and the stability of the radicals formed. Shorter bonds are typically stronger bonds. BDEs for some bonds are given below :
HC–H(g) → HC(g) + H(g) ΔH°=105 kcal mol
Cl–Cl(g) → Cl(g) + Cl(g) ΔH°=58 kcal mol
HC–Cl(g) → HC(g) + Cl(g) ΔH°=85 kcal mol
H–Cl(g) → H(g) + Cl(g) ΔH°=103 kcal mol
For the following reaction
CH(g) + Cl(g) CHCl(g) + HCl (g)
the correct statement is
- (A)Initiation step is exothermic with H = − 58 kcal mol
- (B)Propagation step involving CH formation is exothermic with H = − 2 kcal mol.
- (C)Propagation step involving CHCl formation is endothermic with H = + 27 kcal mol.
- (D)The reaction is exothermic with H = − 25 kcal mol.
For the following reaction scheme, percentage yields are given along the arrow :
g and g are mass of and , respectively.
(Use : Molar mass (in g mol) of H, C and O as 1, 12 and 16, respectively)
The value of is______.
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Treatment of bromine water with propene yields 1-bromopropan-2-ol.
Reason (R) : Attack of water on bromonium ion follows Markovnikov rule and results in 1-bromopropan-2-ol.
In the light of the above statements, choose the most appropriate answer from the options given below :
- (A)Both (A) and (R) are true but (R) is NOT the correct explanation of (A)
- (B)(A) is false but (R) is true.
- (C)Both (A) and (R) are true and (R) is the correct explanation of (A)
- (D)(A) is true but (R) is false
In the following sequence of reactions, the final product D is :
- (A)
- (B)
- (C)
- (D)
Consider the given reaction, the product A is :
- (A)(1)
- (B)(2)
- (C)(3)
- (D)(4)
Excess of isobutane on reaction with in presence of light at gives which one of the following, as the major product?
- (A)
- (B)
- (C)
- (D)
The major product formed in the following reaction is :
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
A chloro compound "A".
(i) forms aldehydes on ozonolysis followed by the hydrolysis.
(ii) when vaporized completely 1.53 g of A, gives 448 mL of vapour at STP.
The number of carbon atoms in a molecule of compound A is ________.
Presence of which reagent will affect the reversibility of the following reaction, and change it to a irreversible reaction:
- (A)HOCl
- (B)Liquid
- (C)dilute
- (D)Concentrated
The dihedral angle in staggered from the Newman projection of 1,1,1,-Trichloro ethane is ______________ degree. (Round off to the Nearest Integer).
An organic compound 'A' on treatment with / yields compound 'B' . Compound 'A' also yields compound 'B' on ozonolysis. Compound 'A' is:
- (A)2-Methylpropene
- (B)1-Methylcyclopropane
- (C)Cyclobutane
- (D)But-2-ene
Consider the above chemical reaction. The total number of stereoisomers possible for product ‘P’ is___________.
Which one of the following molecules does not show stereo isomerism ?
- (A)3 − Ethylhex − 3 − ene
- (B)3 − Methylhex − 1 − ene
- (C)3,4 − Dimethylhex − 3 − ene
- (D)4 − Methylhex − 1 − ene
The number of acyclic structural isomers (including geometrical isomers) for pentene is -.
For above chemical reactions, identify the correct statement from the following
- (A)Both compound 'A' and compound 'B' are dicarboxylic acids.
- (B)Compound 'A' is dicarboxylic acid and compound 'B' is diol.
- (C)Compound 'A' is diol and compound 'B' is dicarboxylic acid.
- (D)Both compound 'A' and compound 'B' are diols.
Metallic sodium does not react normally with :
- (A)gaseous ammonia
- (B)tert – butyl alcohol
- (C)But – 2 – yne
- (D)Ethyne
Benzene on nitration gives nitrobenzene in presence of and mixture, where:
- (A)both and act as a bases
- (B)both and act as an acids
- (C) acts as a base and acts as an acid
- (D) acts as an acid and acts as a base
Match List-I with List-II :
Choose the most appropriate match :
| List-I (Chemicals) | List-II (Use / Preparation / Constituent) |
|---|---|
| a.Alcoholic potassium hydroxide | i.Electrodes in batteries |
| b.Pd/ BaSO | ii.Obtained by addition reaction |
| c.BHC (Benzene hexachloride) | iii.Used for β - elimination reaction |
| d.Polyacetylene | iv.Lindlar's catalyst |
- (A)a-ii, b-i, c-iv, d-iii
- (B)a-iii, b-iv, c-ii, d-i
- (C)a-iii, b-i, c-iv, d-ii
- (D)a-ii, b-iv, c-i, d-iii
Given below are two statements :
Statement-I : 2-methylbutane on oxidation with KMnO gives 2-methylbutan-2-ol.
Statement-II : n-alkanes can be easily oxidised to corresponding alcohol with KMnO.
Choose the correct option :
- (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
Which of the following is Lindlar catalyst ?
- (A)Zinc chloride and HCl
- (B)Cold dilute solution of KMnO
- (C)Sodium and Liquid NH
- (D)Partially deactivated palladised charcoal
An unsaturated hydrocarbon X on ozonolysis gives A. Compound A when warmed with ammonical silver nitrate forms a bright silver mirror along the sides of the test tube. The unsaturated hydrocarbon X is :
- (A)(1)
- (B)(2)
- (C)(3)
- (D)(4)
Identify the reagent(s) 'A' and condition(s) for the reaction :
- (A)A = HCl; Anhydrous AlCl
- (B)A = HCl, ZnCl
- (C)A = Cl; UV light
- (D)A = Cl; dark, Anhydrous AlCl
Considering the above reaction, the major product among the following is:
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
For the given reaction :
What is 'A'
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
The major product of the following reaction is : NO2 H2SO4 NO2
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
Identify A in the given chemical reaction.
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
Consider the following chemical reaction.
HC ≡ CH Product
The number of sp hybridized carbon atom(s) present in the product is _______.
The correct sequence of reagents used in the preparation of 4-bromo-2-nitroethyl benzene from benezene is :
- (A)CHCOCl/AlCl, Br/AlBr, HNO/HSO, Zn/HCl
- (B)CHCOCl/AlCl, Zn-Hg/HCl, Br/AlBr, HNO/HSO
- (C)Br/AlBr, CHCOCl/AlCl, HNO/HSO, Zn/HCl
- (D)HNO/HSO, Br/AlCl, CHCOCl/AlCl, Zn-Hg/HCl
Identify products A and B.
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
What is the major product formed by HI on reaction with ?
- (A)
- (B)
- (C)
- (D)
Consider the following transformations of a compound P.
Choose the correct option(s).
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
The major product obtained from the following reaction is:
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
The major product of the following reaction is:
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
The major product formed in the following reaction is:
- (A)
- (B)
- (C)
- (D)
The major product [C] in the following reaction sequence will be:
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
The major product [R] in the following sequence of reactions is:
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
In the following reaction A is :
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
Which of these will produce the highest yield in Friedel Crafts reaction?
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
The correct order of heat of combustion for following alkadienes is:
- (A)(a) < (b) < (c)
- (B)(a) < (c) < (b)
- (C)(c) < (b) < (a)
- (D)(b) < (c) < (a)
In the following sequence of reactions the maximum number of atoms present in molecule 'C' in one plane is A B C (A is a lowest molecular weight alkyne)
An unsaturated hydrocarbon X absorbs two hydrogen molecules on catalytic hydrogenation, and also gives following reaction: X A B(3-oxo-hexanedicarboxylic acid) X will be :
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
The major product [B] in the following sequence is: CH-C(CH(CH))=CH-CHCH [A] [B]
- (A)CH-CH(CH(CH))-CH=CH-CH
- (B)CH-C(CH(CH))=CH-CHCH
- (C)CH=C(CH(CH))-CHCHCH
- (D)CH-C(CHCHCH)=C(CH)
Consider the following reactions:
Which of these reactions are possible?
- (A)(b) and (d)
- (B)(a) and (d)
- (C)(a) and (b)
- (D)(b), (c) and (d)
Which of the following reactions produce(s) propane as a major product?
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
Total number of hydroxyl groups present in a molecule of the major product \textbf{P} is__________
But-2-ene on reaction with alkaline KMnO at elevated temperature followed by acidification will give :
- (A)One molecule of CHCHO and one molecule of CHCOOH
- (B)2 molecules of CHCHO
- (C)2 molecules of CHCOOH
- (D)CH-CH(OH)-CH(OH)-CH
The major product(s) obtained in the following reaction is/are: (i) KOBu (ii) O/MeS
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
Consider the following reactions :
'A' is:
- (A)CH = CH
- (B)CH – C ≡ CH
- (C)CH ≡ CH
- (D)CH – C ≡ C – CH
The major product of the following addition reaction is: HC – CH=CH
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
The major product obtained in the given reaction is
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
The major product of the following reaction is:
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
The major product of the following reaction is :
- (A)
- (B)
- (C)
- (D)
Polysubstitution is a major drawback in:
- (A)Friedel Craft's alkylation
- (B)Reimer Tiemann reaction
- (C)Acetylation of aniline
- (D)Friedel Craft's acylation
Which one of the following alkenes when treated with HCl yields majorly an anti Markovnikov product?
- (A)
- (B)
- (C)
- (D)
Which of the following has lowest freezing point?
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
The major product of the following reaction is :
- (A)
- (B)
- (C)
- (D)
The correct order for acid strength of compounds: , , is as follows:
- (A)
- (B)
- (C)
- (D)
The major product of the following reaction is :
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
The major product of the following reaction is
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
The major product of the following reaction is:
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
Which hydrogen in compound(E) is easily replaceable during bromination reaction in presence of light?
- (A) - hydrogen
- (B) - hydrogen
- (C) - hydrogen
- (D) - hydrogen
The major product of the following reaction is
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
The major product of the following reaction is:
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
The reaction(s) leading to the formation of 1,3,5-trimethylbenzene is(are)
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
PARAGRAPH 2
The reaction of compound P with (excess) in followed by addition of gives Q. The compound Q on treatment with at 0C gives R. The reaction of R with in the presence of anhydrous in followed by treatment with produces compound S [Et in compound P is ethyl group]
The reactions, Q to R and R to S, are
- (A)Dehydration and Friedel-Crafts acylation
- (B)Aromatic sulfonation and Friedel-Crafts acylation
- (C)Friedel-Crafts alkylation, dehydration and Friedel-Crafts acylation
- (D)Friedel-Crafts alkylation and Friedel-Crafts acylation
Answer by appropriately matching the information given in the three columns of the following table.
Columns 1, 2 and 3 contain starting materials, reaction conditions, and type of reactions, respectively.
The only CORRECT combination in which the reaction proceeds through radical mechanism is
| Column 1 | Column 2 | Column 3 |
|---|---|---|
| (I) Toluene | (i) | (P) Condensation |
| (II) Acetophenone | (ii) | (Q) Carboxylation |
| (III) Benzaldehyde | (iii) | (R) Substitution |
| (IV) Phenol | (iv) | (S) Haloform |
- (A)(I) (ii) (R)
- (B)(II) (iii) (R)
- (C)(III) (ii) (P)
- (D)(IV) (i) (Q)
Among the following, reaction(s) which gives(give) tert-butyl benzene as the major product is(are)
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
In the following reaction, the major product is
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
In the following reactions
The major compound is
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
Schemes 1 and 2 describe sequential transformation of alkynes M and N. Consider only the major products formed in each step for both schemes.
The correct statement with respect to product Y is
- (A)It gives a positive Tollens test and is a functional isomer of X.
- (B)It gives a positive Tollens test and is a geometrical isomer of X.
- (C)It gives a positive iodoform test and is a functional isomer of X.
- (D)It gives a positive iodoform test and is a geometrical isomer of X.
Isomers of hexane, based on their branching, can be divided into three distinct classes as shown in the figure.
The correct order of their boiling point is
- (A)I > II > III
- (B)III > II > I
- (C)II > III > I
- (D)III > I > II
Schemes 1 and 2 describe sequential transformation of alkynes M and N. Consider only the major products formed in each step for both schemes.
The product X is
- (A)(A)
- (B)(B)
- (C)(C)
- (D)(D)
Hydrocarbons — frequently asked
How many questions from Hydrocarbons appear in JEE?
Hydrocarbons has appeared in 126 of the last 186 JEE Main and JEE Advanced papers — about 68% of them — contributing 191 questions in total across those papers.
Is Hydrocarbons an important chapter for JEE?
Judged by how often it is actually tested, it appears in roughly 68% of papers. Chapters above about 50% are effectively guaranteed to show up every session, so they repay thorough preparation; lower-frequency chapters are better treated as targeted revision.
Where do these Hydrocarbons questions come from?
Every question is from an official JEE Main or JEE Advanced paper, transcribed from the original paper and tagged to this chapter. Answers follow the official answer key.
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