Embibe Experts Solutions for Chapter: Haloalkanes and Haloarenes, Exercise 4: EXERCISE-4

Which of the following alkyl halide could br successfully used to synthesize Grignard reagent and why other fail?

(I)

(II) 

(III) 

An alkyl bromide $\mathrm{A}$ has molecular formula ${\mathrm{C}}_8{\mathrm{H}}_{17}\mathrm{Br}$ and four different structures can be drawn for it all optically active. $\mathrm{A}$ on refluxing with ethanolic $\mathrm{KOH}$ solution yields only one elimination product $\mathrm{B}\left({\mathrm{C}}_8{\mathrm{H}}_{16}\right)$ Which is still enantiomeric. $\mathrm{B}$ on treatment with ${\mathrm{H}}_2/\mathrm{pt}$ yields $\mathrm{C}\left({\mathrm{C}}_8{\mathrm{H}}_{18}\right)$ which does not rotate the plane polarized light, $\mathrm{B}$ on ozonolysis followed by work-up with ${\mathrm{H}}_2{\mathrm{O}}_2$ yields $\mathrm{D}\left({\mathrm{C}}_7{\mathrm{H}}_{14}\mathrm{O}\right)$ as one product which is still resolvable. Deduce structures of $\mathrm{A}$ to $\mathrm{D}$.

Identify $\mathrm{B} \mathrm{to} \mathrm{F}$

Vinyl chloride does not give ${\mathrm{S}}_{\mathrm{N}}$ reaction but allyl chloride gives. Explane.

Arrange the following in the increasing order of their ability as a leaving group:

(a) ${\mathrm{CH}}_3{\mathrm{S}}^{-},{\mathrm{CH}}_3{\mathrm{O}}^{-},{{\mathrm{CF}}_3}^{-} \mathrm{and} {\mathrm{F}}^{-}$

(b) ${\mathrm{CF}}_3{{\mathrm{SO}}_3}^{-},{\mathrm{CH}}_3{{\mathrm{SO}}_3}^{-} \mathrm{and} {\mathrm{CH}}_3{\mathrm{COO}}^{-}$

$\mathrm{RBr}$ when treated with $\mathrm{AgCN}$ in a highly polar solvent gives $\mathrm{RNC}$ whereas when it is treated with $\mathrm{NaCN}$ it gives $\mathrm{RCN}$. Explain.

Which is more reactive in each pair towards ${\mathrm{S}}_{\mathrm{N}}$ reaction ?

$\left(\mathrm{A}\right)$ 

$\left(\mathrm{B}\right)$ 

$\left(\mathrm{C}\right)$ 

$\mathrm{D}\stackrel{{\mathrm{LiAlH}}_4}{⟶}\mathrm{E}\stackrel{\frac{{\mathrm{H}}^{+}}{\mathrm{\Delta }}}{⟶}\mathrm{F}\stackrel{\mathrm{NBS}}{⟶}\mathrm{G}\stackrel{ \mathrm{alcoholic} \mathrm{KOH} }{⟶}\mathrm{H}$

Identify $\mathrm{A}$ to $\mathrm{H}.$