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:

### Related Formula textSymmetric Structure propto textMelting Point (Packing efficiency)$$\text{Symmetric Structure} \propto \text{Melting Point (Packing efficiency)}$$ ### Core Logic **Statement (I) is correct**: Neopentane (2,2-dimethylpropane) contains a quaternary carbon bonded to four methyl groups. There are 12 hydrogen atoms, all of which are primary and chemically equivalent. Halogenation yields exactly one monosubstituted derivative: mathrm(CH_3)_4C + X_2 xrightarrowhnu (CH_3)_3C-CH_2X + HX$$\mathrm{(CH_3)_4C + X_2 \xrightarrow{h\nu} (CH_3)_3C-CH_2X + HX}$$ Statement (II) is correct: Neopentane has a compact, symmetrical, nearly spherical molecular structure. In the solid crystal lattice, these spherical molecules pack much more efficiently compared to the floppy, linear n-pentane. This robust crystalline packing dramatically increases its melting point (256.4~mathrmK$256.4~\mathrm{K}$) compared to that of n-pentane (143.4~mathrmK$143.4~\mathrm{K}$). ### Step 1: Final Verification Since both statements are theoretically and experimentally correct, the correct option is (2).

### Pattern Recognition While branching *decreases* the boiling point (due to decreased surface area and weaker van der Waals forces), branching that creates a highly symmetric structure *increases* the melting point because of close-packing efficiency in the solid phase. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Chemistry: Hydrocarbons