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Indian Forest Service (Mains)

Chemistry optional

  • 2 papers
  • 200 marks each
  • 3 h per paper

Paper I covers physical and inorganic chemistry.

Indian Forest Service (Mains), Chemistry optional · 2021 · Paper I

Q6(b). Quantum yield and ethylene production

Question

For the photochemical formation of ethylene from di-n-propyl ketone using a wavelength of 313 nm, the quantum yield is 0.21. Calculate the number of moles of ethylene formed when the sample is irradiated with 50 watt of this radiation, assuming that all the radiation is absorbed by the same sample.

Answer in brief

The data specify a production rate, dn(C₂H₄)/dt = 2.745 × 10⁻⁵ mol s⁻¹; an irradiation time is needed for a total amount.

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Topic notes: photochemistry (quantum yield, Jablonski diagram, H₂–halogen reactions), with every Civil Services, IFoS and Geo-Scientist PYQ →

Coversquantum yieldphoton fluxeinsteindi-n-propyl ketone photolysisNorrish type II

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