Bond energies can be obtained by using the following relation: `DeltaH (reaction) = sum`Bond energy of bonds, broken in the reactants `-sum` Bond energy fo bonds, formed in the products
Bond enegry depends on three factors:
a. Greater is the bond length, lesser is the bond enegry.
b. Bond energy increases with the bond multiplicity.
c. Bond enegry increases with electronegativity difference between the bonding atoms.
Bond enegry of differene halogen molecules will lie in the sequences

Options

A. `F_(2) gt Cl_(2) gt Br_(2) gt I_(2)`
B. `Cl_(2) gt Br_(2) F_(2) gt I_(2)`
C. `I_(2)gt Cl_(2) gt Br_(2) gt F_(2)`
D. `Br_(2) gt F_(2) gt I_(2) gt Cl_(2)`.

Answer

B

Explanation

Bond energy of `F_(2)` is surprisingle low due to strong repulsion between the lone pairs of two fluorine atoms.