The correct order of bond dissociation enthalpy of the halogen molecules is

A $F X_{2} > Cl X_{2} > Br X_{2} > I X_{2}$
B $I X_{2} > Br X_{2} > Cl X_{2} > F X_{2}$
C $Cl X_{2} > Br X_{2} > F X_{2} > I X_{2}$
D $Cl X_{2} > F X_{2} > Br X_{2} > I X_{2}$

Answer: C

The bond enthalpies are about Cl2 242.6, Br2 192.8, F2 158.8 and I2 151.1 kJ/mol. The F-F bond is anomalously weak because of lone-pair repulsion, so F2 falls below Cl2 and Br2.

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The correct order of bond dissociation enthalpy of the halogen molecules is

Answer: C

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