Final answer:
The correct order of the given acids from strongest to weakest is HI, HBr, and HCl, which is based on factors such as bond strength and conjugate base stability.
Step-by-step explanation:
To determine the order of decreasing acid strength for the compounds HCl, HBr, and HI, we consider factors such as bond strength and the stability of the conjugate base. Generally, the strength of these acids increases with decreasing bond strength between the hydrogen and the halogen, which corresponds to an increase in the size of the halogen. Thus, HI is the strongest acid, followed by HBr, and HCl is the weakest due to its stronger H-Cl bond.
For the other parts of the question, to arrange other compounds in order of decreasing acid strength or increasing base strength, we similarly consider the stability of the conjugate bases and the inductive effects that stabilize or destabilize the molecules.
The correct order for the given compounds, taking into account their relative acid strengths in a solvent less basic than water, would be:
- HI (strongest acid)
- HBr
- HCl (weakest acid)