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MHT CET2019Evening ShiftChemistryThermodynamics (C)Actual

Identify the equation in which change in enthalpy is equal to change in internal energy

Options

  1. A2 H 2 O 2 l → 2 H 2 O l + O 2 g
  2. BC s + O 2 g → C O 2 g
  3. CP C l 5 g → P C l 3 g + C l 2 g
  4. DN 2 g + 3 H 2 g → 2 N H 3 g

Correct answer

B. C s + O 2 g → C O 2 g

Step-by-step solution

Key Idea Relationship between change in enthalpy and change in internal energy is given as : Δ H = Δ U + Δ n g R T In the given options, A 2 H 2 O 2 l → 2 H 2 O l + O 2 g Δ n g = 1 ∴ Δ H = Δ U + R T B C s + O 2 g → C O 2 g Δ n g = 1 - 1 = 0 ∴ Δ H = Δ U C P C l 5 g → P C l 3 g + C l 2 g Δ n g R T = 2 - 3 = - 1 ∴ Δ H = - Δ U - R T D N 2 g + 3 H 2 g → 2 N H 3 g Δ n g R T = 2 - 3 = - 1 ∴ Δ H = Δ U - R T

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