JEE Main 2025 Jan 29 Shift 1, Chemistry Q1: Introduction to Mechanism of Organic Reaction

A nucleophile must be electron rich, possessing either a lone pair or a $\pi$-bond that can be donated to an electrophilic centre. Cationic species like ${{\mathrm{H}}_3\mathrm{O}}^{\oplus }$ are electrophiles, not nucleophiles, and the ketone $(\mathrm{C}{\mathrm{H}}_3{)}_2\mathrm{CO}$ together with the imine $(\mathrm{C}{\mathrm{H}}_3{)}_2\mathrm{C}=\mathrm{NC}{\mathrm{H}}_3$ behave as electrophiles at the $\mathrm{C}$ of their polar $\pi$-bond.

The genuine nucleophiles in the list are: $\mathrm{N}{\mathrm{H}}_3$ (N lone pair), $\mathrm{PhSH}$ (S lone pair), $({\mathrm{H}}_3\mathrm{C}{)}_2\mathrm{S}$ (S lone pair), $\mathrm{C}{\mathrm{H}}_2=\mathrm{C}{\mathrm{H}}_2$ (donating $\pi$ electrons), and $\stackrel{\ominus }{\mathrm{O}}\mathrm{H}$ (anionic oxygen).

$\therefore$ Count of nucleophiles $=5$.