A) I > II > III
B) III > II > I
C) II>I> HI
D) II > III > I
Correct Answer: B
Solution :
The rolls of p-dicarbonyl compounds are more stable because of conjugation and intramolecular H-bonding. Thus, the order of stability is \[\underset{\text{III}}{\mathop{\underset{\begin{smallmatrix} (Stabilised\,by\,conjugation \\ and\,H-bonding) \end{smallmatrix}}{\mathop{{{H}_{3}}C-\overset{OH}{\mathop{\overset{|}{\mathop{C}}\,}}\,=CH-\overset{O}{\mathop{\overset{|\,|}{\mathop{C}}\,}}\,-C{{H}_{3}}}}\,}}\,\]\[>C{{H}_{3}}-\overset{O}{\mathop{\overset{||}{\mathop{C}}\,}}\,-C{{H}_{2}}-\overset{O}{\mathop{\overset{|\,\,|}{\mathop{C}}\,}}\,-C{{H}_{3}}\]\[\underset{\begin{smallmatrix} Less\,stable\,as(=)\,bond \\ is\,not\,conjugation\,with\,carbonyl\,group \\ \text{I} \end{smallmatrix}}{\mathop{>C{{H}_{2}}=\overset{OH}{\mathop{\overset{|}{\mathop{C}}\,}}\,-C{{H}_{2}}-\overset{O}{\mathop{\overset{|\,|}{\mathop{C}}\,}}\,-C{{H}_{3}}}}\,\]You need to login to perform this action.
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