MHT CET Chemistry Question (2026) — Solution

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A Lewis acid is a chemical species that can accept a pair of electrons. In BeCl _2, the central beryllium atom forms two single covalent bonds with two chlorine atoms. The valence shell of beryllium in this molecule contains only 4 electrons, which means its octet is incomplete. Due to this electron deficiency, BeCl _2 has a strong tendency to accept electron pairs from other species (Lewis bases) to complete its octet. For example, in the solid state, it forms a polymeric chain structure through coordinate bonding where chlorine atoms donate electron pairs to adjacent beryllium atoms. The other given compounds ( BaCl _2, KCl , LiCl ) are predominantly ionic, and their respective cations have stable noble gas (or duplet) configurations, so they do not act as Lewis acids. Answer: BeCl _2