UPSC Combined Geo-Scientist, Mains · 2026 · Mains Paper II
Q12(a). A unimolecular reaction is second order at low pressure
Question
Show with the help of the hard-sphere collision theory, that a unimolecular elementary gas-phase reaction behaves kinetically as a second order reaction at very low pressure of the reactant.
Model answer
The free solution for 2026 answers the questions picked in its time plan. Question 12 is answered in full in the Book Edition of the 2026 solutions of Geo-Scientist Chemistry Paper II.
CoversLindemann–Hinshelwood mechanismA unimolecular reaction is second order at low pressure
All parts of Question 12
- 12(a) A unimolecular reaction is second order at low pressure10 marks
- 12(b) Quantum yield from an actinometer10 marks