Which of the following is the stronger Brønsted–Lowry acid, HBrO or HBr?

Verified step by step guidance

1. Identify the Brønsted–Lowry acid concept: A Brønsted–Lowry acid is a substance that donates a proton (H⁺) in a chemical reaction.
2. Consider the molecular structure and bond strength: HBr is a binary acid, while HBrO is an oxyacid. Binary acids like HBr typically have stronger acidic properties due to the weaker H-Br bond compared to the H-O bond in HBrO.
3. Evaluate the electronegativity and stability of the conjugate base: The conjugate base of HBr is Br⁻, which is more stable than the conjugate base of HBrO, BrO⁻, due to the lack of additional electronegative atoms that can stabilize the negative charge.
4. Consider the acid dissociation constant (Ka): Generally, a higher Ka value indicates a stronger acid. HBr, being a strong acid, completely dissociates in water, while HBrO is a weak acid with a lower Ka value.
5. Conclude based on the above analysis: HBr is the stronger Brønsted–Lowry acid compared to HBrO due to its complete dissociation and the stability of its conjugate base.

Key Concepts

Brønsted–Lowry Acid-Base Theory

The Brønsted–Lowry theory defines acids as proton donors and bases as proton acceptors. This framework allows for the classification of substances based on their ability to donate or accept protons in a chemical reaction. Understanding this theory is essential for determining the strength of acids and bases in various contexts.

Acid Strength

Acid strength refers to the ability of an acid to donate protons in solution. Stronger acids dissociate more completely in water, releasing more protons, while weaker acids do not dissociate as fully. The strength of an acid can be compared using its dissociation constant (Ka), with larger values indicating stronger acids.

Comparative Analysis of Acids

To determine which acid is stronger between HBrO and HBr, one must compare their dissociation in water. HBr is a strong acid that completely dissociates, while HBrO is a weak acid that does not dissociate fully. This comparative analysis is crucial for identifying the stronger acid based on their behavior in aqueous solutions.