Question

The alkane that gives only one mono-chloro product on chlorination with $Cl_2$ in presence of diffused sunlight is :

• A. 2,2-dimethylbutane
• B. neopentane
• C. n-pentane
• D. Isopentane

Answer 1

The Correct Option is B

To determine which alkane gives only one mono-chloro product upon chlorination with Cl_2 in the presence of diffused sunlight, we must understand the structure of the alkanes provided in the options.

1. Understanding mono-chlorination: Mono-chlorination refers to the replacement of one hydrogen atom in the alkane with a chlorine atom. The ability of an alkane to form only one mono-chloro product depends on the equivalence of the hydrogen atoms in the molecule.
2. Analyzing the options:
   • 2,2-dimethylbutane: This hydrocarbon has multiple types of hydrogen atoms due to its branching, leading to more than one type of mono-chloro product.
   • Neopentane (2,2-dimethylpropane): This molecule is symmetrical, meaning all hydrogen atoms are equivalent. Therefore, chlorination will replace any hydrogen to give the same mono-chloro product.
   • n-pentane: This straight-chain alkane has multiple types of hydrogen (primary and secondary), leading to different mono-chloro products.
   • Isopentane (2-methylbutane): This compound also has non-equivalent hydrogen atoms due to branching, producing different mono-chloro products.
3. Conclusion: Neopentane gives only one type of mono-chloro product because of its symmetrical structure where all the hydrogen atoms are equivalent. Therefore, neopentane is the correct answer.