Moderate

The following graph is given, between total energy and distance between the two nuclei for species H2+, H2, He2+ & He2. Which of the following statements is correct:

Correct answer: B. Bond dissociation energy of H2+ is more than bond dissociation energy of He2+.

  • A. He2+ is more stable than H2+.
  • B. Bond dissociation energy of H2+ is more than bond dissociation energy of He2+.
  • C. Since bond orders of He2+ and H2+ are equal, both will have equal bond dissociation energy.
  • D. Bond length of H2+ is less than bond length of H2.

Explanation

The correct answer is that the bond dissociation energy of H2+ is more than that of He2+. The graph indicates that H2+ reaches a lower energy state, which means more energy is released during its formation, resulting in higher stability and bond dissociation energy. Option A is incorrect because He2+ is less stable due to its higher energy state. Option C is incorrect as it misunderstands the relationship between bond order and energy release; equal bond orders do not imply equal bond dissociation energies. Lastly, Option D is incorrect because the graph does not provide information on bond lengths.

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