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UPSC Civil Services (Mains)

Chemistry optional

  • 2 papers
  • 250 marks each
  • 3 h per paper
  • 5 of 8 questions, Q1 and Q5 compulsory

Paper I covers physical and inorganic chemistry.

UPSC Civil Services (Mains), Chemistry optional · 2022 · Paper I

Q4(a). The state of H₂ corresponding to N₂ at 126 K and 1 atm

Question

By using the following given data, find that under what conditions is H₂ in the state corresponding to N₂ at 126 K and 1 atm? Data: H₂ — Tc = 33 K, Pc = 13 atm; N₂ — Tc = 126 K, Pc = 39 atm.

Answer in brief

H₂ at T = 33 K and P = 0.33 atm (253 torr), where it has the same reduced temperature, Tr = 1.00, and the same reduced pressure, Pr = 0.0256, as the nitrogen.

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Coverslaw of corresponding statesreduced variablescritical constantsvan der Waals equationcompressibility factor

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