Hydrobromic Acid
Definition and meaning of Hydrobromic Acid in chemistry.
Hydrobromic acid is a highly corrosive liquid formed when hydrogen bromide gas dissolves in water. It is a very strong acid that completely breaks apart in an aqueous solution. It separates into positive hydronium ions and negative bromide ions.
In more detail
Many high school students learn about hydrochloric acid, but hydrobromic acid is actually even stronger. Both acids fully split apart when they mix with water. However, the chemical bond between hydrogen and bromine is longer and much weaker.
This weak bond lets the hydrogen atom break away into the water much easier. Because it gives up its hydrogen proton faster, it is considered the stronger acid. You will usually find it sold as a concentrated liquid that is about 48 percent acid by mass.
At this exact concentration, the acid boils at a constant temperature of 124.3 degrees Celsius. Chemists call this type of constant-boiling liquid mixture an azeotrope. The acid is extremely corrosive and can cause severe chemical burns to human skin.
In the chemical industry, it is a hugely important tool for building new chemical molecules. Factories use it to manufacture inorganic metal salts like calcium bromide and zinc bromide. It is also used to create complex carbon compounds needed for farm chemicals and new medicines.
Key facts
| Formula | HBr (in water) |
|---|---|
| Field | Inorganic Chemistry |
| Acid strength | Strong acid, pKa approximately -9 |
| Common concentration | About 48% w/w aqueous solution |
| Boiling point | Azeotrope boils at 124.3 degrees Celsius |
| Safety hazard | Highly corrosive and causes severe burns |
You can use hydrobromic acid to dissolve certain solid reactive metals. If you drop a piece of solid zinc metal into hydrobromic acid, a vigorous chemical reaction quickly starts. The strong acid eats away the solid metal to produce an aqueous solution of zinc bromide. At the same time, it releases rapid bubbles of highly flammable hydrogen gas into the air. The balanced chemical equation for this process is: Zn(s) + 2 HBr(aq) -> ZnBr2(aq) + H2(g).
Frequently asked questions
Is hydrobromic acid stronger than hydrochloric acid?
Yes. The chemical bond between hydrogen and bromine is longer and weaker than the bond in hydrogen chloride. This means hydrobromic acid releases its hydrogen proton more easily into the water.
What is hydrobromic acid used for?
It is used in large factories to make inorganic bromide salts like zinc bromide. It is also used to build complex organic molecules for medicines and agricultural chemicals.
What happens when hydrogen bromide gas dissolves in water?
The gas molecules react with the water and completely split apart. They form positive hydronium ions and negative bromide ions to create a strong liquid acid.
Related terms
Sources & references
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