UPSC Combined Geo-Scientist, Mains · 2025 · Mains Paper II
Q12(c). Pressures for a given coverage on a Langmuir surface
Question
The adsorption of a gas is described by the Langmuir isotherm with α = 0.75 kPa⁻¹ at 298 K. Calculate the pressure at which the fractional surface coverage is (i) 0.15 and (ii) 0.95.
Answer in brief
(i) p = 0.24 kPa; (ii) p = 25 kPa.
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CoversLangmuir adsorption isothermfractional surface coveragemonolayeradsorptionsaturation
All parts of Question 12
- 12(a) t₀.₇₅ = 3 t₀.₅ for a second-order reaction5 marks
- 12(b) Orders in sucrose and H⁺ from half-lives10 marks
- 12(c) Pressures for a given coverage on a Langmuir surface5 marks