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Hydrocarbons

JEE Main 2025 (Online) 2nd April Evening ShiftMCQEasy📈 Topic in 2% papers+4−1
Ques. 1JEE Main 2025, 2 April (Evening Shift)

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. Statement I is correct but Statement II is incorrect
  4. Both Statement I and Statement II are incorrect

Answer

(2) Both Statement I and Statement II are correct

Solution

Statement I: In neopentane, C(CH3)4, all twelve H atoms are equivalent (each is a 1° H on one of four identical -CH3 groups attached to the same quaternary carbon).

Replacing any one H gives the same product, e.g. only one monochloro derivative, (CH3)3C-CH2Cl. Statement I is correct.

Statement II: Melting point depends on how well the molecules pack in the crystal lattice. Neopentane is nearly spherical and highly symmetrical, so it packs far better than the zig-zag n-pentane.

m.p. of neopentane (256.5 K) > m.p. of n-pentane (143.3 K). Statement II is correct.

(Boiling point shows the opposite order, because branching reduces surface area.)

Answer: (2)

Keep practising — Hydrocarbons

Ques. 2JEE Main 2025, 29 January (Evening Shift)

Given below are two statements : 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. Both Statement I and Statement II are false
  4. Statement I is false but Statement II is true
Ques. 3JEE Main 2025, 29 January (Evening Shift)

Isomeric hydrocarbons negative Baeyer's test (Molecular formula C9H12) The total number of isomers from above with four different non-aliphatic substitution sites is -

Ques. 4JEE Main 2025, 28 January (Morning Shift)

A molecule (P) on treatment with acid undergoes rearrangement and gives (Q). (Q) on ozonolysis followed by reflux under alkaline condition gives (R). The structure of (R) is given below. [figure] The structure of (P) is

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
Ques. 5JEE Main 2025, 28 January (Evening Shift)

Identify product [A], [B] and [C] in the following reaction sequence. CH3-C CH [H2]Pd/C [A] [(ii) Zn, H2O](i) O3 [B] + [C]

  1. [A]: CH3-CH=CH2, [B]: CH3CHO, [C]: CH3CH2OH
  2. [A]: CH3-CH=CH2, [B]: CH3CHO, [C]: HCHO
  3. [A]: CH3CH2CH3, [B]: CH3CHO, [C]: HCHO
  4. [A]: CH2=CH2, [B]: H3C- O \|C-CH3, [C]: HCHO
Ques. 6JEE Main 2025, 24 January (Morning Shift)

The product (A) formed in the following reaction sequence is [figure]

  1. CH3-CH2- OH |CH-CH2-NH2
  2. CH3-CH2- NH2 |CH-CH2-NH2
  3. CH3- CH3 | OH |C-CH2-NH2
  4. CH3- CH3 | NH2 |C-CH2-OH
Ques. 7JEE Main 2025, 24 January (Morning Shift)

Following are the four molecules "P", "Q", "R" and "S". Which one among the four molecules will react with H-Br(aq) at the fastest rate? [figure]

  1. Q
  2. S
  3. P
  4. R
Ques. 8JEE Main 2025, 24 January (Evening Shift)

Identify correct statement/s : Choose the correct answer from the options given below :

  1. A, C and D only
  2. A, B and E only
  3. A and C only
  4. A only
Ques. 9JEE Main 2025, 23 January (Morning Shift)

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?

  1. 4
  2. 2
  3. 3
  4. 5
Ques. 10JEE Main 2025, 23 January (Evening Shift)

Match List - I with List - II Choose the correct answer from the options given below :

  1. A-III, B-IV, C-I, D-II
  2. A-I, B-IV, C-III, D-II
  3. A-III, B-II, C-I, D-IV
  4. A-II, B-II, C-I, D-IV
Ques. 11JEE Main 2025, 23 January (Evening Shift)

A compound ' X ' absorbs 2 moles of hydrogen and ' X ' upon oxidation with KMnO4 | H+ gives [figure] The total number of bonds present in the compound ' X ' is .

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