Question

Choose the correct statement(s) for the given structures :

• A. Bond lengths of both $C-O$ bonds in structure I are equal
• B. Bond lengths of both $C-O$ bonds in structure II are equal
• C. Bond lengths of both $C-O$ bonds in structure I are unequal
• D. Bond lengths of both $C-O$ bonds in structure II are unequal

Answer 1

Answer: (B), (C)

Bond lengths of both $C-O$ bonds in structure I are unequal

For structure I:


For structure I the resonating structures that are shown are non-equivalent resonating structures since one is neutral and other has charges on it.
Hence, both $C-O$ bond lengths in $C{H}_{3}COOH$ are unequal.
For structure II :

For sructure II, resonating structures are equivalent and both are negatively charged. Thus, both $C-O$ bond lengths in $C{H}_{3}CO{O}^{-}$ are equal .

Resonance hybrid for acetate ion is :