The increasing order of the rate of HCN addit | vedclass

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(A) The rate of nucleophilic addition of $HCN$ to carbonyl compounds depends on two factors:$1$. Steric hindrance: As the size of the groups attached

Vedclass · Accepted Answer

$D < C < B < A$

Vedclass · Answer

(A) The rate of nucleophilic addition of $HCN$ to carbonyl compounds depends on two factors:$1$. Steric hindrance: As the size of the groups attached to the carbonyl carbon increases,the rate of nucleophilic attack decreases.$2$. Electronic effects: Electron-donating groups (like alkyl groups) decrease the electrophilicity of the carbonyl carbon,while electron-withdrawing groups (like phenyl rings via resonance) also decrease the reactivity compared to aliphatic counterparts.Comparing the given compounds:$(A)\ HCHO$ (Formaldehyde): No alkyl groups,least steric hindrance,most reactive.$(B)\ CH_3COCH_3$ (Acetone): Two methyl groups,more steric hindrance than $HCHO$.$(C)\ PhCOCH_3$ (Acetophenone): One phenyl group and one methyl group. The phenyl group provides resonance stabilization to the carbonyl carbon,reducing its electrophilicity.$(D)\ PhCOPh$ (Benzophenone): Two phenyl groups,highest steric hindrance and significant resonance stabilization,making it the least reactive.Thus,the reactivity order is $HCHO > CH_3COCH_3 > PhCOCH_3 > PhCOPh$.The increasing order is $D < C < B < A$.

The increasing order of the rate of $HCN$ addition to the following compounds is:
$(A)\ HCHO$
$(B)\ CH_3COCH_3$
$(C)\ PhCOCH_3$
$(D)\ PhCOPh$

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The increasing order of the rate of $HCN$ addition to the following compounds is:$(A)\ HCHO$$(B)\ CH_3COCH_3$$(C)\ PhCOCH_3$$(D)\ PhCOPh$