Which one is a strong nucleophile:
Correct answer: B. H-O-
- A. C6 H5O
- B. H-O-
- C. NH3
- D. C2 H5 O-
Explanation
Nucleophilicity increases as the density of negative charge increases. An anion is always a better nucleophile than a neutral molecule, so the conjugate base is always a better nucleophile. A highly electronegative atom is a poor nucleophile because it is unwilling to share its electrons. A has ring system so increased charge density thus stronger nucleophile. H-O- is a strong nucleophile as it has a negative charge and a small size, which allows it to easily donate its lone pair of electrons to form a bond with a positive or electrophilic atom or group.
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About Nucleophilic Substitution
Nucleophilic substitution replaces a leaving group in an alkyl halide when an electron-rich nucleophile attacks the carbon atom. The topic compares SN1 and SN2 mechanisms, including reaction conditions, substrate structure, solvent effects, nucleophile strength, carbocation formation and stereochemical changes, and distinguishes substitution from elimination.
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