NEET2026ChemistryChapterActual
Consider the following chemical species: (I) CH ₃ S ⁻ (II) CH ₃ O ⁻ (III) CH ₃ COO ⁻ (IV) H ₂ O Which of the following represents the correct increasing order of their nucleophilicity in a polar protic solvent?
Options
- A(IV) < (III) < (I) < (II)
- B(IV) < (III) < (II) < (I)
- C(III) < (IV) < (II) < (I)
- D(I) < (II) < (III) < (IV)
Correct answer
B. (IV) < (III) < (II) < (I)
Step-by-step solution
Nucleophilicity depends on the charge, basicity, polarizability, and the nature of the solvent. Among the given species, H ₂ O (IV) is a neutral molecule, making it the weakest nucleophile compared to the negatively charged ions. For the oxygen-containing anions, nucleophilicity parallels basicity. The basicity order is CH ₃ O ⁻ > CH ₃ COO ⁻ . The acetate ion, CH ₃ COO ⁻ (III), is resonance stabilized, which delocalizes the negative charge and makes it a weaker nucleophile than the localized methoxide ion, CH ₃ O ⁻