Concept:Bond energy is inversely proportional to bond length. Shorter bonds are stronger because the nuclei are closer to the shared electron pair.
Formula:$$ \text{Bond Energy} \propto \frac{1}{\text{Bond Length}} $$
Solution:- Fluorine is the smallest halogen atom. When it bonds with Hydrogen, the resulting H-F bond length is extremely short.
- Because the bonding electrons are held very tightly and closely between the two nuclei, a massive amount of energy (approx. 567 kJ/mol) is required to break the bond.
- As we go down the halogen group (Cl, Br, I), the atomic size increases, bond length increases, and bond energy rapidly decreases.
Why other options are incorrect:- Option A, Option C, Option D: These molecules feature progressively larger halogens, resulting in longer, weaker bonds that are easier to break.
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