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AP EAMCET20226 Jul 2022Morning ShiftChemistryThermodynamics (C)Actual

From the following data at 25^ C , calculate the _ r H ^0 for H ₂ O ( g ) 2 H ( g )+ O ( g ) reaction: _ r H ^0 ( ~kJ ~mol ⁻¹ ) array ll 1 2 H ₂( ~g )+ 1 2 O ₂( ~g ) OH ( g ) & 42.09 H ₂( ~g )+ 1 2 O ₂( ~g ) H ₂ O ( g ) & -242 H ₂( ~g ) 2 H ( g ) & 436 O ₂( ~g ) 2 O ( g ) & 496 array

Options

  1. A1174 ~kJ ~mol ⁻¹
  2. B742 ~kJ ~mol ⁻¹
  3. C926 ~kJ ~mol ⁻¹
  4. D690 ~kJ ~mol ⁻¹

Correct answer

C. 926 ~kJ ~mol ⁻¹

Step-by-step solution

H ₂ O ( g ) H ₂( ~g )+ 1 2 O ₂( ~g ) ; H =+242 ~kJ / mol aligned & H ₂( ~g ) 2 H ; H =+436 ~kJ / mol & 1 2 O ₂( ~g ) O ; H =+ 496 2 ~kJ / mol =248 ~kJ / mol aligned By adding up above three equations: _ r H =242+436+248=926 ~kJ / mol

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