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KVPY2019ChemistryThermodynamics (C)

For a spontaneous process,

Options

  1. Aenthalpy change of the system must be negative
  2. Bentropy change of the system must be positive
  3. Centropy change of the surrounding must be positive
  4. Dentropy change of the system plus surrounding must be positive

Correct answer

D. entropy change of the system plus surrounding must be positive

Step-by-step solution

For a spontaneous process in an isolated system, the change in entropy is positive, i.e, Δ S > O . However, if a system is not isolated, the entropy change of both the system and surroundings are to be taken into account because system and surroundings together constitute the isolated system thus, the total entropy change Δ S total  is sum of the change in entropy of the system Δ S system  and the change in entropy of the surroundings Δ S purroundings  i.e., Δ S total&#16

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