Bond energy of $\mathrm{Cl}_2, \mathrm{Br}_2$ and $\mathrm{I}_2$ follow the order

Bond energy of $\mathrm{Cl}_2, \mathrm{Br}_2$ and $\mathrm{I}_2$ follow the order
  1. $\mathrm{Cl}_2>\mathrm{Br}_2>\mathrm{I}_2$
  2. $\mathrm{Br}_2>\mathrm{Cl}_2>\mathrm{I}_2$
  3. $\mathrm{I}_2>\mathrm{Br}_2>\mathrm{Cl}_2$
  4. $\mathrm{I}_2>\mathrm{Cl}_2>\mathrm{Br}_2$

Solution

As the size of atom increases, $A-A$ bond length increases and hence, $A-A$ bond energy decreases. (where $A=\mathrm{Cl}, \mathrm{Br}, \mathrm{I})$ $\therefore$ The order of bond energy is $\mathrm{Cl}_2>\mathrm{Br}_2>\mathrm{I}_2$

Asked in: AP EAMCET 2012

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