Ionisation Enthalpy, Oxidation States — Predicted 2026
AI-Predicted Question Angles for UPSC 2026
Comparative stability of oxidation states in different environments.
highNEET often tests nuanced understanding. A question might compare the stability of an oxidation state in aqueous solution versus in a solid compound, or with different ligands. For example, why is $Fe^{3+}$ more stable than $Fe^{2+}$ in air, but $Fe^{2+}$ is common in some biological systems? Or, how does the presence of strong field ligands affect the stability of higher oxidation states in complexes? This requires understanding hydration enthalpy, lattice energy, and ligand field effects.
Application of ionisation enthalpy to predict reactivity or redox potential.
mediumInstead of direct questions on IE values, NEET might ask how IE values correlate with the reducing or oxidizing power of transition metals. For instance, a metal with a low $IE_1$ and $IE_2$ would be a strong reducing agent. Questions could involve comparing the ease of forming $M^{2+}$ ions across the 3d series based on their $IE_1$ and $IE_2$ values, and relating it to their standard electrode potentials.
Identifying elements based on their unique ionisation enthalpy or oxidation state patterns.
mediumA question might describe a set of properties (e.g., 'An element X in the 3d series shows only one oxidation state and has a very high $IE_3$. Identify X.') and ask the student to identify the element. This tests the ability to synthesize information about both properties and apply it to specific elements like Sc or Zn, which have distinct characteristics.