Embibe Experts Solutions for Chapter: Hydrocarbons, Exercise 4: EXERCISE-4

$2$-Butyne undergoes following reactions in steps as indicated. Identify $\mathrm{A}$ to $\mathrm{H}$

Identify $\mathrm{A},\mathrm{B},\mathrm{C}$ with proper explanation.

A hydrocarbon $\mathrm{A}\left({\mathrm{C}}_{10}{\mathrm{H}}_{12}\right)$ has no chiral carbon. A gives a white precipitate with ammonical solution of silver nitrate. $\mathrm{A}$ on treatment with ${\mathrm{H}}_2/\mathrm{Pt}$ gives $\mathrm{B}\left({\mathrm{C}}_{10}{\mathrm{H}}_{20}\right)$. $\mathrm{A}$ ozonolysis gives $\mathrm{C}\left({\mathrm{C}}_8{\mathrm{H}}_{12}{\mathrm{O}}_4\right)$ as one product which on heating with soda lime gives $\mathrm{D}\left({\mathrm{C}}_6{\mathrm{H}}_{12}\right)$. $\mathrm{D}$ on monochlorination with ${\mathrm{Cl}}_2/\mathrm{hv}$ gives ${\mathrm{C}}_6{\mathrm{H}}_{11}\mathrm{Cl}$ as sole isomer. Identify $\mathrm{A}$ to $\mathrm{D}$

Identify $\mathrm{A}$ to $\mathrm{D}$ in the following scheme.

Write structure of ${\mathrm{C}}_4{\mathrm{H}}_9\mathrm{Cl}$.

Specify the reagents in which addition to alkene is syn or anti

(i) ${\mathrm{Br}}_2$ water

(ii) ${\mathrm{H}}_2/\mathrm{pd}$

(iii) ${\mathrm{MnO}}_4^{-}/{\mathrm{OH}}^{-}$

(iv) ${\mathrm{HCO}}_3\mathrm{H}$

(v) $\mathrm{MCPBA}$

(vi) ${\mathrm{OsO}}_4$ in ether, followed by $\mathrm{O}\overline{\mathrm{H}}/{\mathrm{H}}_2\mathrm{O}$

${\mathrm{C}}_5{\mathrm{H}}_{10}$ represents three isomeric alkenes ${\mathrm{A}}_1,{\mathrm{A}}_2$ and ${\mathrm{A}}_3$. Each on hydrogenation gives $2$-methylbutane. ${\mathrm{A}}_1$ and ${\mathrm{A}}_2$ on oxymercuration-demercuration give the same $3°$ alcool. ${\mathrm{A}}_2$ and ${\mathrm{A}}_3$ on hydroboration oxidation give different $1°$ alcohol. Assign structures to ${\mathrm{A}}_1,{\mathrm{A}}_2$ and ${\mathrm{A}}_3$ and explain reactions.

Hydration of $3-$phenyl$-1-$butene in dilute ${\mathrm{H}}_2{\mathrm{SO}}_4$ is not a satisfactory method for preparing $3-$phenyl$-2-$butanol, because$2-$phenyl$-2-$butanol is obtained instead. Explain.