Question

Of HI and HCl which has a weaker covalent bond and what effect has it on their acid strengths?

Answer 1

1. HI has a weaker covalent bond compared to HCl because the bond dissociation energy decreases from HCl (432 kJ/mol) to HI (295 kJ/mol).
2. Due to the weaker \[\ce{H - I}\] bond, HI dissociates more easily in water, releasing H₃O⁺ ions, so it is a stronger acid than HCl.
3. The acid strength order is HF < HCl < HBr < HI, showing that weaker \[\ce{H - X}\] bonds lead to stronger acids.
4. Thus, HI’s weaker bond results in higher acid strength compared to HCl.