Question

Identify the group that exerts electron withdrawing resonance effect.

Options

• \[\ce{- NHR}\]

• \[\ce{- COOH}\]

• \[\ce{- OR}\]

• \[\ce{- OH}\]

Answer 1

\[\ce{- COOH}\]

Explanation:

The \[\ce{- COOH}\]  group has an electron withdrawing resonance effect when compared to the other options. It has an adjacent π-system that has π-bond to an electronegative atom (i.e. - C = 0), which deactivates the aromatic ring by reducing the electron density on the ring due to a resonance withdrawing action.