Down group 17 the acids run HF, HCl, HBr, HI. Which trend in acid strength is seen and why?

1. In a binary hydride the proton has to be released from the hydrogen to nonmetal bond. 2. Going down a group that bond becomes progressively weaker. 3. A weaker bond is easier to break, so the proton is released more readily. 4. Acid strength therefore rises down the group, giving HF weakest and HI strongest. 5. Electronegativity falls down the group, so it cannot be what drives this trend. _Source: OpenStax Chemistry (CC BY 4.0), Ch 14 "Acid-Base Equilibria", section 14.3 Relative Strengths of Acids and Bases_