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NEETChemistryThermodynamics (C)

For the reaction Cl ₂( g ) 2 Cl ( g ) , what are the respective signs of the enthalpy change ( H ) and entropy change ( S )?

Options

  1. AH is negative, S is positive
  2. BH is positive, S is negative
  3. CH is negative, S is negative
  4. DH is positive, S is positive

Correct answer

D. H is positive, S is positive

Step-by-step solution

The given reaction is Cl ₂( g ) 2 Cl ( g ) . First, consider the enthalpy change ( H ). The process involves the dissociation of a Cl - Cl bond to form isolated chlorine atoms. Bond breaking always requires an input of energy, making the process endothermic. Therefore, H is positive. Second, consider the entropy change ( S ). One mole of gaseous molecules is converted into two moles of gaseous atoms. Since the number of gaseous particles increases, the randomness and disorder of the system increase. Therefore, S is

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