When the acids, `H_(2)Se`, HBr and HI are arranged in order of increasing strength (Weakest acid first), which is the correct order?

Options

A. `HBrltHIltH_(2)Se`
B. `HBrltH_(2)SeltHI`
C. `H_(2)SeltHBrltHI`
D. `HIltH_(2)SeltHBr`

Answer

To determine the order of increasing strength of the acids H₂Se, HBr, and HI, we will analyze their acidic properties step by step.

### Step 1: Understand Acid Strength
Acid strength is determined by the ability of the acid to donate a proton (H⁺). The more stable the conjugate base (the species that remains after the acid donates a proton), the stronger the acid.

### Step 2: Compare H₂Se and HBr
- **H₂Se**: This acid contains selenium, which is in Group 16 of the periodic table. Selenium is less electronegative than bromine, meaning it holds onto its electrons less tightly.
- **HBr**: This acid contains bromine, which is in Group 17. Bromine is more electronegative than selenium, which means that the conjugate base Br⁻ is more stable than SeH⁻.

Since HBr has a more stable conjugate base, it is a stronger acid than H₂Se.

### Step 3: Compare HBr and HI
- **HI**: This acid contains iodine, which is also in Group 17. Iodine is larger than bromine, and the bond between H and I (H-I) is longer and weaker than the bond between H and Br (H-Br). A weaker bond means that HI can lose its proton more easily than HBr can.

Thus, HI is a stronger acid than HBr.

### Step 4: Final Comparison
From the comparisons:
- H₂Se < HBr (H₂Se is weaker than HBr)
- HBr < HI (HBr is weaker than HI)

### Conclusion
Arranging the acids in order of increasing strength (weakest acid first), we have:
**H₂Se < HBr < HI**

### Final Answer
The correct order of increasing strength of the acids is:
**H₂Se, HBr, HI**

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