Which of the following groups exhibits the strongest (electron donating) effect? — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

The $+I$ effect is exerted most strongly by atoms carrying a formal negative charge (anions) because they intensely repel electron density away from themselves. Among anions, the less electronegative or more highly charged the atom, the stronger the $+I$ effect. Oxygen in $-O^-$ is a stronger donor than the resonance-stabilized $-COO^-$.