Question

The increasing order of reduction of alkyl halides with zinc and dilute $HCl$ is

• A. $R-Cl<R-Br<R-I$
  
  
• B. $R-Br<R-I<R-Cl$
• C. $R-Cl<R-I<R-Br$
  
  
  
  
• D. $R-I<R-Br<R-Cl$
  
  

Answer 1

The correct option is A $R-Cl<R-Br<R-I$



The reduction of alkyl halides with zinc and dilute $HCl$ depends on strength of $C-X$ bond ($X\to \text{halogen})$.

As the bond strength of $C-X$ increases, the reactivity of reduction of alkyl halides decreases.
Bond strength order for $C-X$ is
$C-I<C-Br<C-Cl$
Thus, increasing order of reduction of alkyl halides with zinc and dilute HCl is :
$R-Cl<R-Br<R-I$
Hence, option (B) is correct.