Species X is a Group 15 trihalide which cannot act as a Lewis acid because its central atom cannot expand its octet. Species Y is a Group 15 pentahalide that acts as a very powerful oxidizing agent due to the high instability of the +5 oxidation state of its central atom. Identify Species X and Species Y respectively from the given options.

Step-by-step solution

Species X is a Group 15 trihalide that cannot act as a Lewis acid. A Lewis acid must be able to accept an electron pair. Nitrogen trihalides (like NCl₃ ) cannot accept an electron pair because the central nitrogen atom belongs to the second period and lacks vacant d-orbitals to expand its octet. Heavier trihalides like PCl₃ have vacant d-orbitals and can act as Lewis acids by expanding their octet. Thus, Species X is NCl₃ . Species Y is a Group 15 pentahalide that acts as a powerful oxidizing agent. Down Group 15,