Which one of the following orders is correct for the bond dissociation enthalpy of halogen molecules
I2 > Br2 > Cl2 > F2
Cl2 > Br2 > F2 > I2
Br2 > I2 > F2 > Cl2
F2 > Cl2 > Br2 > I2
Bond strength -
The energy required to break one mole of bonds of particular type in gaseous state is called bond energy or bond strength.
- wherein
The same amount of energy is released in formation of one mol of particular bond.
Bond dissociation enthalpies of halogen family decreased down the group as the size of atom increases. The bond dissociation enthalpy of fluorine, is however, lower than those of cheorine and bromine because of inter electronic repusion present in small atoms of flourine.
Hence order of bond dissociation enthalpies for halogen is
Option 1)
I2 > Br2 > Cl2 > F2
This is incorrect option
Option 2)
Cl2 > Br2 > F2 > I2
This is correct option
Option 3)
Br2 > I2 > F2 > Cl2
This is incorrect option
Option 4)
F2 > Cl2 > Br2 > I2
This is incorrect option