Arrhenius, Br??nsted-Lowry and Lewis Concepts — Predicted 2026

AI-Predicted Question Angles for UPSC 2026

Based on trend analysis, current affairs, and recurring themes in Arrhenius, Br??nsted-Lowry and Lewis Concepts.

Identification of Lewis acids/bases in complex ions or organic reactions.

high

As NEET increasingly integrates concepts across chapters, questions might involve identifying Lewis acids (e.g., metal ions in coordination compounds, carbocations in organic reactions) or Lewis bases (e.g., ligands, carbanions). This tests a deeper application of the Lewis theory beyond simple $BF_3/NH_3$ examples, requiring students to recognize electron-deficient centers or lone pair availability in more complex structures. Understanding the role of catalysts like $AlCl_3$ in Friedel-Crafts reactions as Lewis acids is also a likely angle.

Comparative analysis of acid-base strength based on conjugate pairs.

medium

While direct strength comparisons are often covered in separate chapters, questions might link the Brønsted-Lowry concept to relative strengths. For example, 'Given a strong acid, what can be said about its conjugate base?' or 'Which of the following conjugate bases is the weakest?' This requires applying the principle that a strong acid has a weak conjugate base and vice versa. This angle tests not just identification but also the implications of conjugate relationships.

Reactions in non-aqueous solvents and their classification.

low

While less common, a question might present a reaction in a non-aqueous solvent (e.g., liquid ammonia) and ask to classify the reactants as Brønsted-Lowry acids/bases. This directly tests the advantage of the Brønsted-Lowry concept over Arrhenius. It's a good way to check if students truly understand the scope of each theory beyond just aqueous systems. For example, $NH_3 + NH_3 ightleftharpoons NH_4^+ + NH_2^-$ where one $NH_3$ acts as an acid and the other as a base.

Multi-concept questions involving amphiprotic species.

high

Questions that combine the identification of an amphiprotic species with its behavior as both an acid and a base in different reactions are highly probable. For instance, a question could provide two reactions involving $H_2PO_4^-$ and ask to identify its role (acid/base) and its conjugate pair in each specific reaction. This tests the nuanced understanding of amphiprotic behavior and conjugate pairs simultaneously.