Class 12 NEET Chemistry Aldehydes, Ketones And Carboxylic Acids Part 1

The ease of dehydration of the given compounds can be explained on the basis of the stability of the carbocation formed,In case of options (a), (b) and (d), a secondary carbocation is formed but the presence of an electron withdrawing >C=O group adjacent to the positively charged carbon, intensifies the charge and hence destabilises the species.However, in case of option (c), a secondary carbocation is formed, but the electron withdrawing >C=O group is present farther away, as a result, the effect of this group is diminished and hence the carbocation is relatively more stable.