Which of the following is not a nucleophile?

Explanation

Br₂ is not a nucleophile because:No Significant Negative Charge:Nucleophiles are electron-rich species that donate electrons.Br₂ is a neutral molecule with no formal negative charge, making it less likely to donate electrons.Weak Electron Donation Ability:Even though Br atoms have lone pairs, they are held tightly and not readily available for donation.Instead, Br₂ tends to act as an electrophile (electron acceptor), especially in reactions like electrophilic addition.Polarizability but No Strong Nucleophilic Character:Br₂ is a polarizable molecule, meaning it can momentarily develop dipoles, but this does not make it a nucleophile.In reactions, Br₂ often undergoes heterolytic cleavage, forming Br⁺ (electrophile) and Br⁻ (nucleophile), where only Br⁻ is nucleophile.