JEE MainChemistryHydrocarbons
An unknown structural isomer 'X' of C₅H₁₂ is found to have the highest melting point among all its isomers. The number of structurally isomeric monochloro derivatives that 'X' can form upon photochemical chlorination, and its boiling point compared to n-pentane, respectively, are :
Options
- A3 and higher
- B1 and higher
- C1 and lower
- D4 and lower
Correct answer
C. 1 and lower
Step-by-step solution
Among the structural isomers of C₅H₁₂ , neopentane (2,2-dimethylpropane) has the highest melting point due to its highly symmetrical spherical structure, which allows it to pack closely in the crystal lattice. Therefore, isomer 'X' is neopentane. Neopentane has 12 equivalent primary hydrogen atoms. Thus, it forms only 1 monochloro derivative upon photochemical chlorination. The boiling point of alkanes decreases with an increase in branching due to a decrease in surface area and consequently weaker van der Waals fo