JEE MAIN - Chemistry (2024 - 1st February Morning Shift - No. 15)
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Haloalkanes react with KCN to form alkyl cyanides as a main product while with $\mathrm{AgCN}$ form isocyanide as the main product.
Reason (R) : $\mathrm{KCN}$ and $\mathrm{AgCN}$ both are highly ionic compounds.
In the light of the above statements, choose the most appropriate answer from the options given below :
Assertion (A) : Haloalkanes react with KCN to form alkyl cyanides as a main product while with $\mathrm{AgCN}$ form isocyanide as the main product.
Reason (R) : $\mathrm{KCN}$ and $\mathrm{AgCN}$ both are highly ionic compounds.
In the light of the above statements, choose the most appropriate answer from the options given below :
(A) is correct but $(\mathbf{R})$ is not correct
Both (A) and (R) are correct and (R) is the correct explanation of (A)
(A) is not correct but (R) is correct
Both (A) and (R) are correct but (R) is not the correct explanation of (A)
Explanation
$\begin{aligned} & \mathrm{R}-\mathrm{X}+\mathrm{KCN} \longrightarrow \mathrm{R}-\mathrm{CN}+\mathrm{KX} \\\\ & \mathrm{R}-\mathrm{X}+\mathrm{AgCN} \longrightarrow \mathrm{R}-\mathrm{NC}+\mathrm{AgX}\end{aligned}$
$\mathrm{KCN}$ is ionic so it provides cyanide ions in solution and attacks from carbon side on alkyl halide.
But $\mathrm{AgCN}$ is covalent it cannot form cyanide ion so it attacks from nitrogen side and isocyanide is formed predominantly.
$\mathrm{A}$ is correct $\mathrm{R}$ is not correct.
$\mathrm{KCN}$ is ionic so it provides cyanide ions in solution and attacks from carbon side on alkyl halide.
But $\mathrm{AgCN}$ is covalent it cannot form cyanide ion so it attacks from nitrogen side and isocyanide is formed predominantly.
$\mathrm{A}$ is correct $\mathrm{R}$ is not correct.
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