The K_{eq.} values in HCN addition to the fol | vedclass

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(D) The addition of $HCN$ to an aldehyde is a nucleophilic addition reaction. The equilibrium constant $K_{eq.}$ depends on the electrophilicity of th

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$II > I > III$

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(D) The addition of $HCN$ to an aldehyde is a nucleophilic addition reaction. The equilibrium constant $K_{eq.}$ depends on the electrophilicity of the carbonyl carbon.Electron-donating groups (like $-OCH_3$ and $-N(CH_3)_2$) decrease the electrophilicity of the carbonyl carbon by resonance ($+M$ effect),thereby decreasing the $K_{eq.}$ value.Comparing the substituents:- In $(II)$,there is no substituent on the benzene ring.- In $(I)$,the $-OCH_3$ group exerts a $+M$ effect.- In $(III)$,the $-N(CH_3)_2$ group exerts a stronger $+M$ effect than $-OCH_3$.Therefore,the electrophilicity order is $(II) > (I) > (III)$,which is also the order of $K_{eq.}$ values.Thus,the correct order is $II > I > III$.

List-$I$ (Type of reaction)	List-$II$ (Final Product)
$A$. Reimer-Tiemann reaction	$I$. Chlorobenzene
$B$. Etard reaction	$II$. Salicylaldehyde
$C$. Sandmeyer reaction	$III$. Benzaldehyde
$D$. Friedel-Crafts reaction	$IV$. Acetophenone

The $K_{eq.}$ values in $HCN$ addition to the following aldehydes are in the order:

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