Which one of the following order is correct fo the bond energies of halogen molecules?
A. `I_2 gt Cl_2 gt Br_2`
B. `Br_2 gt Cl_2 gt I_2`
C. `I_2 gt Br_2 gt Cl_2`
D. `Cl_2 gt Br_2 gt I_2`

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1 Answers

Correct Answer - D
Order of atomic radii: Cl lt Br lt I
Order of X-X bond length: `Cl_2 lt Br_2 lt I_2`
Shorter the bond, stronger the bond, more is the bond energy. Therefore, B.E. are in the order `Cl_2 gt Br_ 2 gt I_2`
However, the trend for `F_2`, is not what is expected from bond length data.

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