Arrange the following acids in the decreasing order of their acid strength:
`HF, HCl, HBr, HI`

Explanation

To arrange the acids HF, HCl, HBr, and HI in decreasing order of their acid strength, we can follow these steps:

### Step 1: Understand Acid Strength
Acid strength is determined by the ability of an acid to donate a proton (H⁺). The stronger the acid, the more readily it donates a proton.

### Step 2: Identify the Conjugate Bases
When these acids dissociate in solution, they produce their respective conjugate bases:
- HF → F⁻
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