Is Hydrobromic Acid (HBr) a Strong or Weak Acid?
Is Hydrobromic Acid (HBr) a strong or weak acid?
HBr is a strong acid, even stronger than HCl. Bromine is larger than chlorine, making the H-Br bond weaker and easier to break. The bromide ion is very stable due to its large size.
| Formula | HBr |
| Name | Hydrobromic Acid |
| Category | Strong acid |
| pKa | -9 |
| Conjugate | Bromide ion (Br⁻) |
| Key Concept | Compare with HCl |
Definition
HBr is a strong Bronsted-Lowry acid that donates its proton completely to water. It is stronger than HCl because bromine is larger and the H-Br bond is weaker.
Acidic Proton / Active Site
The hydrogen bonded to bromine is the acidic proton. The H-Br bond (366 kJ/mol) is weaker than H-Cl (431 kJ/mol) due to the larger size of Br.
Conjugate Pair
HBr donates H+ to form Br- (bromide). Bromide is a very weak conjugate base - it is large and stable, with little tendency to grab a proton back.
Strength Classification
HBr has pKa = -9. Among hydrohalic acids, acidity increases down the group: HF < HCl < HBr < HI. Larger atoms form weaker bonds with hydrogen.
See acidic protons, conjugate base overlays, and pKa labels on interactive 3D molecules.
Explore Hydrobromic Acid's Acid-Base Properties in 3DRelated Topics
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Acidity Ranking
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