question_answer

                Polarization of electrons in acrolein may be written as:                                                                  

A)                 \[\overset{\delta +}{\mathop{C}}\,{{H}_{2}}=CH-CH=\overset{\delta -}{\mathop{O}}\,\]                            

B)                 \[\overset{\delta +}{\mathop{C}}\,{{H}_{2}}=\overset{\delta +}{\mathop{CH}}\,-CH=\overset{{}}{\mathop{O}}\,\]

C)                 \[\overset{\delta +}{\mathop{C}}\,{{H}_{2}}=\overset{{}}{\mathop{CH}}\,-CH=\overset{\delta +}{\mathop{O}}\,\]                                        

D)                 \[\overset{\delta +}{\mathop{C}}\,{{H}_{2}}=\overset{{}}{\mathop{CH}}\,-\overset{\delta +\,\,}{\mathop{CH}}\,=\overset{{}}{\mathop{O}}\,\]

Correct Answer: A

Solution :

                                In \[C{{H}_{2}}=CH-CHO\]due to ?M effect of -CHO group polarization of electron takes place as follows                                 Hence, partial polarization is represented as                 \[\overset{\delta +}{\mathop{C{{H}_{2}}}}\,=CH-CH=\overset{\delta -}{\mathop{O}}\,\]