Physical and Chemical Properties — Predicted 2026

AI-Predicted Question Angles for UPSC 2026

Based on trend analysis, current affairs, and recurring themes in Physical and Chemical Properties.

Multi-step Synthesis involving Aldehydes/Ketones

high

NEET often includes multi-step reaction sequences. A question might start with an alcohol, oxidize it to an aldehyde/ketone, then subject it to an aldol condensation or a Grignard reaction. Students need to identify intermediates and final products. For example, 'Compound A ($C_3H_8O$) on oxidation gives B. B reacts with dilute NaOH and then heated to give C. Identify A, B, C.' This tests multiple concepts in one go.

Reactivity Comparison with Steric/Electronic Justification

medium

Beyond just stating that aldehydes are more reactive, a question might ask for the *reason* behind the difference in reactivity between specific aldehydes and ketones (e.g., formaldehyde vs. acetaldehyde vs. acetone). This requires understanding the interplay of steric hindrance and electron-donating effects of alkyl groups. For instance, 'Arrange the following in increasing order of reactivity towards HCN: Propanone, Ethanal, Formaldehyde, Benzaldehyde.'

Application of Protecting Groups

low

While less common for NEET, the concept of protecting groups (e.g., formation of acetals/ketals to protect a carbonyl group during a reaction on another part of the molecule) could be introduced. This tests the understanding of reversible reactions and selective reactivity. For example, a molecule with both a carbonyl and another reactive group might be given, and students need to identify the steps to selectively react one group.

Crossed Aldol Condensation Products

medium

Simple aldol condensation is common. Crossed aldol condensation, especially when one reactant lacks \$\alpha\$-hydrogens (e.g., benzaldehyde with ethanal), simplifies product prediction and is a good test of understanding the mechanism and selectivity. Questions might ask for the major product when two different aldehydes react, or when an aldehyde reacts with a ketone.