In the fundamental chemical reaction , which chemical species acts by the mechanism of a Lewis acid? — Ionic Equilibrium Chemistry Question

💡 Solution & Explanation

According to the Lewis acid-base mechanism, an acid is an electron-pair acceptor. In the formation of the triiodide ion, the iodide ion ($I^-$) donates an electron pair (acting as a Lewis base), while the neutral iodine molecule ($I_2$) accepts the electron pair into its empty antibonding orbital, thereby acting strictly as a Lewis acid.