Arrange the carbanions, \(\left(\mathrm{CH}_{3}ight)_{3} \mathrm{C}^{-}, \mathrm{Cl}_{3} \mathrm{C}^{-}…

Arrange the carbanions, \(\left(\mathrm{CH}_{3}ight)_{3} \mathrm{C}^{-}, \mathrm{Cl}_{3} \mathrm{C}^{-},\left(\mathrm{CH}_{3}ight)_{2} \mathrm{CH}^{-}, \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CH}_{2}^{-}\), in order of their decreasing stability.
  1. \(\mathrm{Cl}_{3} \mathrm{C}^{-}>\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CH}_{2}^{-}>\left(\mathrm{CH}_{3}ight)_{2} \mathrm{CH}^{-}>\left(\mathrm{CH}_{3}ight)_{3} \mathrm{C}^{-}\)
  2. \(\left(\mathrm{CH}_{3}ight)_{3} \mathrm{C}^{-}>\left(\mathrm{CH}_{3}ight)_{2} \mathrm{CH}^{-}>\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CH}_{2}^{-}>\mathrm{Cl}_{3} \mathrm{C}^{-}\)
  3. \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CH}_{2}^{-}>\mathrm{Cl}_{3} \mathrm{C}^{-}>\left(\mathrm{CH}_{3}ight)_{3} \mathrm{C}^{-}>\left(\mathrm{CH}_{3}ight)_{2} \mathrm{CH}^{-}\)
  4. \(\left(\mathrm{CH}_{3}ight)_{2} \mathrm{CH}^{-}>\mathrm{Cl}_{3} \mathrm{C}^{-}>\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CH}_{2}^{-}>\left(\mathrm{CH}_{3}ight)_{3} \mathrm{C}^{-}\)

Solution

The carbanion \(\left(\mathrm{CH}_{3}ight)_{3} \mathrm{C}^{-}\)is expected to be least stable due to electron-releasing nature of methyl groups. The carbanion \(\mathrm{Cl}_{3} \mathrm{C}^{-}\)is expected to be most stable due to electron-attracting nature of chlorine atoms Keeping only these two facts in mind, the choice (a) seems to be correct. ^

Asked in: JEE-TOPICTESTS-CHEMISTRY

Practice more ORGANIC CHEMISTRY – SOME BASIC PRINCIPLES AND TECHNIQUES questions on Aicharya