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Hydrocarbons · Question 10

JEE Main 2026 (Online) 28th January Morning ShiftMCQMedium📈 Topic in 26% papers+4−1
1

Given below are two statements for the following reaction sequence. [figure] In the light of the above statements, choose the correct answer from the options given below :

  1. Statement I is true but Statement II is false
  2. Both Statement I and Statement II are true
  3. Statement I is false but Statement II is true
  4. Both Statement I and Statement II are false

Answer

(2) Both Statement I and Statement II are true

Solution

X (C3H6Cl2, e.g. CH3CCl2CH3) undergoes double dehydrohalogenation with excess NaNH2:

CH3CCl2CH3 excess NaNH2 CH3-C CH (propyne, Y)

Z: hydration of propyne with dil. H2SO4 / Hg2+ follows Markovnikov's rule:

CH3-C CH + H2O Hg2+, H+ CH3COCH3 (propanone, Z)

Z is a methyl ketone (CH3CO-), so it gives the iodoform test: with NaOI it forms a yellow precipitate of CHI3. Statement I is true.

Q: as per NCERT, alkynes passed through a red hot iron tube at 873 K undergo cyclic polymerisation; three molecules of propyne give mesitylene (1,3,5-trimethylbenzene), C9H12:

[figure]

Aromatic H = 3 (one on each free ring carbon), aliphatic H = 9 (three CH3 groups)

aromatic : aliphatic = 3 : 9 = 1 : 3. Statement II is true.

Answer: (2)

JEE Main 2026 (Online) 28th January Morning Shift

Keep practising — Hydrocarbons

2

Ph-CH=CH2 [HBr](PhCOO)2 Product Consider the above reaction Identify the correct statements. Choose the correct answer from the options given below :

  1. A & E Only
  2. A, B & D Only
  3. A, C & E Only
  4. C, D & E Only
JEE Main 2026 (Online) 28th January Morning Shift
3

The reactions which produce alcohol as the product are : Choose the correct answer from the options given below :

  1. B, D and E Only
  2. A and D Only
  3. A, C and E Only
  4. C and D Only
JEE Main 2026 (Online) 28th January Evening Shift
4

Consider the following compounds : [figure] Arrange these compounds in the increasing order of reactivity with nitrating mixture.

  1. c < b < a
  2. b < c < a
  3. c < a < b
  4. b < a < c
JEE Main 2026 (Online) 23rd January Morning Shift
5

But-2-yne and hydrogen (one mole each) are separately treated with (i) Pd/C and (ii) Na/ liq. NH3 to give the products X and Y respectively. [figure] Identify the incorrect statements. Choose the correct answer from the options given below :

  1. B and D Only
  2. A and C Only
  3. A and B Only
  4. B and C Only
JEE Main 2026 (Online) 23rd January Morning Shift
6

[figure] Identify (P)

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
JEE Main 2026 (Online) 23rd January Evening Shift
7

Given below are two statements : In the light of the above statements, choose the most appropriate answer from the options given below

  1. Statement I is incorrect but Statement II is correct
  2. Both Statement I and Statement II are correct
  3. Both Statement I and Statement II are incorrect
  4. Statement I is correct but Statement II is incorrect
JEE Main 2026 (Online) 22nd January Morning Shift
8

The cycloalkene (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)

JEE Main 2026 (Online) 22nd January Morning Shift
9

Consider the following reaction : [figure] The product Y formed is :

  1. 2-methylhex-3-yne
  2. 5-methylhex-2-yne
  3. Isopropylbut-1-yne
  4. 2-methylhex-2-yne
JEE Main 2026 (Online) 22nd January Evening Shift
10

The dibromo compound [P] (molecular formula: 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 Tollens' test. The compound [P] is :

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
JEE Main 2026 (Online) 22nd January Evening Shift
11

Identify A in the following reaction. [figure]

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
JEE Main 2026 (Online) 21st January Morning Shift

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All JEE Main Chemistry chapters
Physical ChemistrySome Basic Concepts of ChemistryStructure of AtomStates of MatterThermodynamicsEquilibriumRedox ReactionsSolutionsElectrochemistryChemical Kinetics
Inorganic ChemistryClassification of Elements and Periodicity in PropertiesChemical Bonding and Molecular Structurep-Block Elements (Group 13 & 14)p-Block Elements (Group 15–18)d- and f-Block ElementsCoordination Compounds
Organic ChemistryOrganic Chemistry – Some Basic Principles and TechniquesIsomerismHydrocarbonsHaloalkanes and HaloarenesAlcohols, Phenols and EthersAldehydes, Ketones and Carboxylic AcidsAminesBiomoleculesPrinciples Related to Practical Chemistry