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MHT CET Medical202626 April 2026Morning ShiftChemistryThermodynamics (C)Actual

The relationship between H and U for the reaction, PCl ₃(g) + Cl ₂(g) PCl ₅(g) is given as

Options

  1. AH = U + 2RT
  2. BH = U - 2RT
  3. CH = U + RT
  4. DH = U - RT

Correct answer

D. H = U - RT

Step-by-step solution

The given reaction is PCl ₃(g) + Cl ₂(g) PCl ₅(g) The relationship between enthalpy change ( H ) and internal energy change ( U ) is given by the equation: H = U + n_g RT where n_g is the change in the number of moles of gaseous species. n_g = moles of gaseous products - moles of gaseous reactants n_g = 1 - (1 + 1) = -1 Substituting n_g = -1 in the equation, we get: H = U - RT Answer: H = U - RT

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