Chemistry - Hydrocarbon Question with Solution | TestHub

A. ${\mathrm{CH}}_3-\mathrm{CH}={\mathrm{CH}}_2\stackrel{\mathrm{HCl}\text{ (Peroxide) }}{\to }$

The peroxide effect is only observed with HBr, not HCl. Therefore, this reaction will follow Markownikoff's rule, yielding 2-chloropropane.

B. ${\mathrm{CH}}_3-\mathrm{CH}=\mathrm{CH}-{\mathrm{CH}}_3\underset{\text{ Peroxide }}{\overset{\mathrm{HBr}}{\to }}$

This is a symmetrical alkene (but-2-ene). Markownikoff's and anti-Markownikoff's rules are relevant for unsymmetrical alkenes. The product will be 2-bromobutane, regardless of the rule.

C. ${\left({\mathrm{CH}}_3\right)}_2\mathrm{C}={\mathrm{CH}}_2\stackrel{\mathrm{NOCl}}{\to }$

This is the addition of nitrosyl chloride (NOCl), which does not follow Markownikoff's or anti-Markownikoff's rule.

D. ${\left({\mathrm{CH}}_3\right)}_2\mathrm{C}={\mathrm{CH}}_2\stackrel{\mathrm{HBr}/\text{ Peroxide }}{\to }$

This is an unsymmetrical alkene (2-methylpropene) reacting with HBr in the presence of peroxide. This is the classic condition for anti-Markownikoff's addition.

The product will be 1-bromo-2-methylpropane.

Reaction for option D:

$${\left({\mathrm{CH}}_3\right)}_2\mathrm{C}={\mathrm{CH}}_2+\mathrm{HBr}\stackrel{\text{ Peroxide }}{\to }{\left({\mathrm{CH}}_3\right)}_2\mathrm{CH}-{\mathrm{CH}}_2\mathrm{Br}$$

The final answer is $\boxed{D}$