Question

Which has highest bond energy and stronger bond ?

• A. $F_2$
• B. $C{l}_2$
• C. $B{r}_2$
• D. $I_2$

Answer 1

Answer: (B)

Bond energy of $C{l}_2$ is highest among all halogen molecules. Bond energy of $F_2,C{l}_2,B{r}_2,I_2$ are $37,58,46$ and $36$ $kcalmo{l}^{-1}$, respectively. On moving down the group of halogens, the bond energy decreases from chlorine to bromine and to iodine. Fluorine has lower bond energy due to interelectronic repulsions due to small sized $F$ atom.