UPSC Combined Geo-Scientist, Mains · 2019 · Mains Paper I
Q2(c). Lewis acidity of boron halides
Question
Define Lewis acid and Lewis base. Arrange BF₃, BCl₃ and BBr₃ in the increasing order of their acid strength.
Answer in brief
A Lewis acid accepts an electron pair and a Lewis base donates one. The conventional adduct-forming acidity order is BF₃<BCl₃<BBr₃.
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CoversLewis acidity of boron halidesLewis acids and bases
All parts of Question 2
- 2(a) Weak-acid titration indicator10 marks
- 2(b) Equilibrium constant from cell potential10 marks
- 2(c) Lewis acidity of boron halides5 marks
- 2(d) Radius ratio and coordination5 marks