question_answer

                \[\overset{\begin{smallmatrix}  \odot - \\  \centerdot \,\,\centerdot  \end{smallmatrix}}{\mathop{C{{H}_{2}}}}\,-\underset{\begin{smallmatrix}  |\,\,\,| \\  O \end{smallmatrix}}{\mathop{C}}\,-C{{H}_{3}}\] and \[C{{H}_{2}}=\underset{\begin{align}   & | \\  & _{\centerdot }^{\centerdot }O\,_{\centerdot }^{\centerdot } \\  & \centerdot \,\,\centerdot  \\  & \odot - \\ \end{align}}{\mathop{C}}\,-C{{H}_{3}}\] are:                                                                                     

A)                 resonating structures

B)                 tautomers          

C)                 geometrical isomers                                      

D)                 optical isomers

Correct Answer: A

Solution :

                                                  Structure I and structure II are the resonating forms because the position of atoms remains the same and only electron redistribution takes place.