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QJEEAdv20Chc2fe: JEE Advanced 2020 Chemistry - Class 11 JEEAdv20Chc2fe Solution: The figure below is the plot of potential energy versus…

The figure below is the plot of potential energy versus internuclear distance (d) of H2 molecule in the electronic ground state. What is the value of the net potential energy E0 (as indicated in the figure) in kJ mol-1, for d = d0 at which the electron-electron repulsion and the nucleus-nucleus repulsion energies are absent? As reference, the potential energy of H atom is taken as zero when its electron and the nucleus are infinitely far apart.
Use Avogadro constant as 6.023 ×\times 1023 mol-1.

JEE Advanced 2020 Paper 2 Offline Chemistry - Structure of Atom Question 6 English

Step-by-Step Verified Solution

Given that, electrons and nucleus are at infinite distance, so potential energy of H-atom is taken as zero.

Therefore, according to Bohr's model, potential energy of a H-atom with electron in its ground state = −- 27.2 eV

At d = d0, nucleus-nucleus and electron-electron repulsion is absent.

Hence, potential energy will be calculated for 2 H atoms = −- 2 ×\times 27.2 eV = −- 54.4 eV

Potential energy of 1 mol H atoms in kJ

= 54.4×6.02×1023×1.6×10−191000{{54.4 \times 6.02 \times {{10}^{23}} \times 1.6 \times {{10}^{ - 19}}} \over {1000}}

= −5242.4192- 5242.4192 kJ/mol

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