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MHT CET202616 April 2026Morning ShiftChemistryThermodynamics (C)Actual

What is the change in entropy of surrounding for the reaction, H _ 2(g) + 1/2 O _ 2(g) H ₂ O _ (l) at 298 K if standard enthalpy of formation of water is -286 kJ ?

Options

  1. A959.7 JK ⁻¹
  2. B801.5 JK ⁻¹
  3. C850.7 JK ⁻¹
  4. D980.0 JK ⁻¹

Correct answer

A. 959.7 JK ⁻¹

Step-by-step solution

The standard enthalpy of formation of water is the enthalpy change of the system for the given reaction. H_ sys = -286 kJ = -286000 J The heat absorbed by the surroundings at constant pressure is given by: q_ surr = - H_ sys = 286000 J The change in entropy of the surroundings is calculated as: S_ surr = q_ surr T Substituting the given values: S_ surr = 286000 298 = 959.7 J K ⁻¹ Answer: 959.7 JK ⁻¹

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