| 67 | Great! You've got the correct answer!
        
          and hopefully, these are the reasons that made you decide this way:
            | The isomer | 
              
                
                  | D) |  |  | is identical to the di-ketene in question. |  
        Now continue to page 70 for a
short summary and the conclusion of this section!D) gives rise to two NMR signals
from the protons in the CH2= and >CH2
groups.The ratio of the intensities is 1 : 1,
since both of the two groups contain two equivalent protons. 
 |