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 :

Both Statement I and Statement II are correct

Statement I is incorrect but Statement II is correct

Statement I is correct but Statement II is incorrect

Both Statement I and Statement II are incorrect

Hydrocarbons PYQ — JEE Main 2025 · 2 Apr · Shift 2 · Q1 with Solution

View written solutionFree

Correct answer: B

Analyze Statement (I): Neopentane forms only one monosubstituted derivative.
- Neopentane is $2,2$ -dimethylpropane.
- Its structure is highly symmetrical: $\mathrm{C(CH_3)_4}$
- All $12$ hydrogen atoms in neopentane are equivalent because the four methyl groups are identical by symmetry.
- Therefore, replacing any one hydrogen by another atom/group gives the same monosubstituted product.
Hence, Statement (I) is correct.
Analyze Statement (II): Melting point of neopentane is higher than n-pentane.
- In general, branching lowers boiling point, but melting point depends strongly on molecular symmetry and crystal packing.
- Neopentane is highly symmetrical, so it packs more efficiently in the crystal lattice.
- Better packing increases lattice stability, which raises the melting point.
- Thus, neopentane has a higher melting point than the less symmetrical $n$ -pentane.
Hence, Statement (II) is also correct.
Choose the correct option:

Since both statements are correct, the correct choice is: $\boxed{\text{B}}$
Comparison with stored correct answer:
- Derived answer: $\boxed{\text{B}}$
- Stored correct answer: $\boxed{\text{B}}$
They match.

View written solutionFree

Correct answer: B

Analyze Statement (I): Neopentane forms only one monosubstituted derivative.
- Neopentane is $2,2$ -dimethylpropane.
- Its structure is highly symmetrical: $\mathrm{C(CH_3)_4}$
- All $12$ hydrogen atoms in neopentane are equivalent because the four methyl groups are identical by symmetry.
- Therefore, replacing any one hydrogen by another atom/group gives the same monosubstituted product.
Hence, Statement (I) is correct.
Analyze Statement (II): Melting point of neopentane is higher than n-pentane.
- In general, branching lowers boiling point, but melting point depends strongly on molecular symmetry and crystal packing.
- Neopentane is highly symmetrical, so it packs more efficiently in the crystal lattice.
- Better packing increases lattice stability, which raises the melting point.
- Thus, neopentane has a higher melting point than the less symmetrical $n$ -pentane.
Hence, Statement (II) is also correct.
Choose the correct option:

Since both statements are correct, the correct choice is: $\boxed{\text{B}}$
Comparison with stored correct answer:
- Derived answer: $\boxed{\text{B}}$
- Stored correct answer: $\boxed{\text{B}}$
They match.