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JEE Main202528 Jan 2025Morning ShiftChemistryThermodynamics (C)Actual

The formation enthalpies, H _ f for H _ ( g ) and O _ ( g ) are 220.0 and 250.0 ~kJ ~mol ⁻¹ , respectively, at 298.15 K , and H _ f ^ for H ₂ O _ ( g ) is -242.0 ~kJ ~mol ⁻¹ at the same temperature. The average bond enthalpy of the O - H bond in water at 298.15 K is __________ kJ mol ⁻¹ (nearest integer).

Correct answer

0

Step-by-step solution

aligned & 1 2 H _ 2( ~g ) H ( g ) ; _ f H ( H _ ( g ) )=220 KJ / mol & 1 2 O _ 2( ~g ) O ( g ) ; _ f H ( O _ ( g ) )=250 KJ / mol aligned aligned & H _ f ( H ₂ O _ ( l ) )=-242=440+250-2( ~B . E .( O - H )) & BE ( O - H )=466 KJ / mol aligned

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