Group 13 Elements: The Boron Family — Predicted 2026
AI-Predicted Question Angles for UPSC 2026
Application of Inert Pair Effect
highThe inert pair effect is a fundamental concept for p-block elements. Future questions are likely to test its application, such as comparing the stability of $TlCl$ vs $TlCl_3$ or asking about the most stable oxidation state of Indium or Gallium. Students might be asked to identify compounds where the inert pair effect is significant or to explain its consequences on reactivity. This concept is often a source of confusion, making it a good discriminator for NEET.
Structure and Bonding in Diborane and Boric Acid
highThe unique 'banana bond' structure of diborane ($B_2H_6$) and the layered, hydrogen-bonded structure of boric acid ($H_3BO_3$) are distinctive features of Boron chemistry. Questions frequently probe the hybridization of boron, the number of 3c-2e bonds, or the nature of boric acid as a Lewis acid. Visual representation and understanding of these structures are key, making them high-probability questions for NEET.
Anomalous Properties of Boron and Diagonal Relationship
mediumBoron's distinct behavior from its heavier congeners (non-metallic, electron-deficient, max covalency 4) and its diagonal relationship with Silicon are classic topics. Questions might involve comparing properties of Boron with Aluminium or Silicon, or asking for reasons behind Boron's anomalous behavior. This tests a student's understanding of periodic trends and exceptions, which is a core area for NEET.
Lewis Acid Strength of Boron Trihalides and Back-bonding
mediumThe counter-intuitive trend in Lewis acid strength of $BX_3$ (where $BI_3 > BBr_3 > BCl_3 > BF_3$) due to back-bonding is a sophisticated concept often tested. Questions might ask for the correct order or the reason behind it, requiring an understanding of orbital overlap and electron donation. This tests a deeper conceptual understanding beyond simple electronegativity trends.