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Fluorosulfuric acid

physical science Maturity 11-13 Next article →

Fluorosulfuric acid is a very powerful liquid. It belongs to a group called superacids. A superacid is stronger than 100% sulfuric acid.

This liquid is colorless in its pure form. However, many samples look yellow. These yellow colors come from tiny impurities. It is one of the strongest acids that people can buy for work. It is a very important chemical for science.

This acid works in a very specific way. It is a tetrahedral molecule. This means its shape looks like a four-sided pyramid.

It is closely related to sulfuric acid. One part of the sulfuric acid is replaced by a fluorine atom. This change makes it much stronger. It can dissolve almost all organic compounds. These are things made mostly of carbon. It even helps change how certain oils work.

Scientists use different methods to make this acid. One way is to react hydrogen fluoride with sulfur trioxide.

Another way involves using a hot liquid called oleum. This happens at a temperature of 250 degrees Celsius. To clean the acid, scientists use an inert gas. This gas sweeps the hydrogen fluoride away. Then, the acid can be distilled in glass tools. This is how they get the pure liquid.

There are many important numbers for this acid. Its H0 value is -15.1. For comparison, sulfuric acid has a value of -12.

At a temperature of 298 K, its self-ionization is 4.0 times 10 to the power of -8. It can also be used as a fluorinating agent in labs. This means it helps add fluorine to other things. Some people mix it with antimony pentafluoride. This creates something called "Magic acid." This mixture is a far stronger protonating agent.

Working with this acid requires great care. It is highly toxic and extremely corrosive. This means it can eat through many materials.

If it touches water, it reacts very violently. This reaction is even stronger than the reaction with sulfuric acid. When it meets water, it turns into two other things. It becomes hydrogen fluoride and sulfuric acid. Scientists must handle it with extreme caution.

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