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The standard enthalpy of formation of NH_3 is -46.0 ~kJ ~mol^-1. If the enthalpy of formation of H_2 from its atoms is -436 ~kJ ~mol^-1 and that of…

JEE Main 2010 — Chemistry Physical Chemistry

2010mcqmedium

The standard enthalpy of formation of NH3\mathrm{NH}_3NH3​ is −46.0 kJ mol−1-46.0 \mathrm{~kJ} \mathrm{~mol}^{-1}−46.0 kJ mol−1. If the enthalpy of formation of H2\mathrm{H}_2H2​ from its atoms is −436 kJ mol−1-436 \mathrm{~kJ} \mathrm{~mol}^{-1}−436 kJ mol−1 and that of N2\mathrm{N}_2N2​ is −712 kJ mol−1-712 \mathrm{~kJ} \mathrm{~mol}^{-1}−712 kJ mol−1, the average bond enthalpy of N−H\mathrm{N}-\mathrm{H}N−H bond in NH3\mathrm{NH}_3NH3​ is

Official previous-year question

Held on 30 Apr 2010 · Verified 6 Jul 2026.

Options

  1. A

    −964 kJ mol−1-964 \mathrm{~kJ} \mathrm{~mol}^{-1}−964 kJ mol−1

  2. B

    +352 kJ mol−1+352 \mathrm{~kJ} \mathrm{~mol}^{-1}+352 kJ mol−1

  3. C

    +1056 kJ mol−1+1056 \mathrm{~kJ} \mathrm{~mol}^{-1}+1056 kJ mol−1

  4. D

    −1102 kJ mol−1-1102 \mathrm{~kJ} \mathrm{~mol}^{-1}−1102 kJ mol−1

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