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JEE Main 2025 Apr 2 Shift 2, Chemistry Q3: Properties of Alkanes

JEE Main2025Apr 2, Shift 2Chemistry
Q.

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 :

  1. A

    Statement I is correct but Statement II is incorrect

  2. B

    Both Statement I and Statement II are correct

  3. C

    Both Statement I and Statement II are incorrect

  4. D

    Statement I is incorrect but Statement II is correct

Solution

Neopentane, , has all twelve hydrogen atoms in an equivalent chemical environment. Free-radical halogenation can therefore replace any one of them to give a single monohalogenated product, . Statement I is correct.

The compact, near-spherical shape of neopentane allows much tighter packing in the solid state than the zig-zag chain of n-pentane. This higher symmetry raises the lattice energy and gives neopentane a significantly higher melting point () than n-pentane (). Statement II is correct.

Both statements are correct.

Concept behind this question

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