Q39 / 180 · KCET 2022 · Chemistry
Identify the products $A$ and $B$ in the reactions :
$$
\begin{aligned}
& R-X+\mathrm{AgCN} \longrightarrow A+\mathrm{Ag} X \\
& R-X+\mathrm{KCN} \longrightarrow B+\mathrm{KX}
\end{aligned}
$$
- A$A=R C \mathrm{~N} ; B=R \mathrm{NC}$
- Correct answerB$A=R \mathrm{NC} ; B=R C N$
- C$A=R \mathrm{NC} ; B=R \mathrm{NC}$
- D$A=R-\mathrm{CN}: B=R \mathrm{CN}$
Solution
$R-X+\mathrm{AgCN} \longrightarrow R \mathrm{NC}+\mathrm{Ag} X$
$$
R-X+\mathrm{KCN} \longrightarrow R \mathrm{CN}+\mathrm{KX}
$$
$\mathrm{KCN}$ is predominantly ionic in nature, its $\mathrm{C}-$. . bond is more stable than $\mathrm{C}-\mathrm{N}$ bond. $T^{\prime}$ :. refore, in this case attack takes place through carbon atom. On other hand, $\mathrm{AgCN}$ is predominantly covalent in nature, hence only nitrogen is available for bonding result in formation of $R \mathrm{NC}$.
Hence, the correct answer is option: 'B'.