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Hydrocarbons · Question 7

JEE Main 2026 (Online) 4th April Evening ShiftMCQMedium📈 Topic in 26% papers+4−1
1

[figure] 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. 90
  2. 118
  3. 160
  4. 125

Answer

(2) 118

Solution

(i) Br2/CHCl3: addition to the side-chain C=C ⇒ vicinal dibromide, C6H5CHBr-CH2Br

(ii) Excess NaNH2: two dehydrobromination steps give phenylacetylene; the extra NaNH2 removes the acidic terminal H ⇒ sodium phenylacetylide, C6H5C C Na

(iii) CH3I: alkylation of the acetylide ⇒ C6H5C C-CH3 (1-phenylpropyne)

(iv) Na/liquid NH3 (Birch reduction): anti addition of hydrogen ⇒ trans-alkene, C6H5CH=CH-CH3 = (Y)

[figure]

(Y) = C9H10 ⇒ M = 9 × 12 + 10 × 1 = 118 g mol-1

Answer: (2)

JEE Main 2026 (Online) 4th April Evening Shift

Keep practising — Hydrocarbons

2

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 .

JEE Main 2026 (Online) 2nd April Morning Shift
3

The compound (X) on (i) on heating in the presence of anhydrous 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. Hept-2-ene
  2. Hept-1,3,5-triene
  3. Heptane
  4. Hept-2,4,6-triene
JEE Main 2026 (Online) 2nd April Evening Shift
4

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
JEE Main 2026 (Online) 28th January Morning Shift
5

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
6

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
7

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
8

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
9

[figure] Identify (P)

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
JEE Main 2026 (Online) 23rd January Evening Shift
10

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
11

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

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