Indian Forest Service (Mains), Chemistry optional · 2025 · Paper I
Q2(c)(ii). Bonding and magnetism of B₂
Question
“B₂ has a bond order of one and is paramagnetic.” Substantiate.
Answer in brief
The two highest electrons singly occupy degenerate bonding π(2p) orbitals, giving bond order one and two unpaired electrons.
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CoversB₂ molecular orbital diagrams–p mixingparamagnetismbond orderHund's rule
All parts of Question 2
- 2(a)(i) Hydrogen equation in spherical coordinates10 marks
- 2(a)(ii) Box length from an emission frequency5 marks
- 2(b)(i) Lifetime and spectral uncertainty5 marks
- 2(b)(ii) Dissociation energies of dioxygen species10 marks
- 2(c)(i) Ordering molecular dipoles5 marks
- 2(c)(ii) Bonding and magnetism of B₂5 marks