Verified Solution • 2025–26 Session
moderate
QNEET-2016-Ch-1020: NEET 2016 Chemistry - Class 12 NEET-2016-Ch-1020 Solution: Which one of the following orders is correct for the bond…
Which one of the following orders is correct for the bond dissociation enthalpy of halogen molecules?
Multiple Choice Options
- A Br 2 > I 2 > F 2 > Cl 2
- B F 2 > Cl 2 > Br 2 > I 2
- C I 2 > Br 2 > Cl 2 > F 2
- D Cl 2 > Br 2 > F 2 > I 2
Step-by-Step Verified Solution
Bond dissociation enthalpy decreases as the bond distance increases from F2 to I2. This is due to increase in the size of the atom, on moving from F to I.
F � F bond dissociation enthalpy is smaller then Cl � Cl and even smaller than Br � Br. This is because F atom is very small and hence the three lone pairs of electrons on each F atom repel the bond pair holding the F-atoms in F 2 molecules.
The order of bond dissociation enthalpy is :
Cl 2 > Br 2 > F 2 > I 2