Chemistry Formulas

Hydrofluoric Acid Formula

Hydrofluoric acid is basically the aqueous solution of hydrogen fluoride. We also refer to it as fluoric acid or fluorhydric acid. In this article, we will study the Hydrofluoric acid formula and its various properties to get a better understanding.

Formula and Structure

Let’s take a look at the chemical formula of Hydrofluoric acid. It is HF. Further, the molar mass of the same is 20.01 g/mol. Moreover, hydrogen fluoride is the gaseous form whereas the hydrofluoric acid is the solution of HF in water. Other than that, HF is basically a simple diatomic molecule which has a structure that is given below:

Hydrofluoric Acid Formula

Hydrogen fluoride gets polarize because of the electronegativity of the fluoride. This allows the H+ to be easily detached. Therefore, it becomes an acid.


In order to industrially prepare hydrofluoric acid, it will require the reaction of fluorite (CaF2) along with concentrated sulphuric acid at a very high temperature (265 °C). Due to this reaction, hydrogen fluoride and calcium sulfate are produced which is given below:

CaF2 + H2SO4 → 2 HF + CaSO4

After that, we dissolve hydrogen fluoride gas in water in order to create hydrofluoric acid, in various concentrations.

Physical Properties

Hydrogen fluoride is a gas which is colourless and has got a density of 1.15 g/L which is at room temperature or it remains a colourless liquid below the temperature of 20°C having a density of 0.99 g/mL. The solution of Hydrofluoric acid is a colourless solution. Other than that, regarding the physical properties of the HF, like its density, melting point and boiling point, it varies because it is dependent on the concentration of HF in the aqueous solution.

Chemical Properties

Hydrofluoric acid is quite a strong acid which is also very reactive and corrosive. It actively reacts with acids, oxidants and bases. If we talk about one of its finest reactions, it is definitely the corrosive and dissolving effect it has on the glass and ceramics which we refer to as etching. Moreover, because of the reactivity towards glass and metals, we usually store them in plastic containers.


Hydrofluoric acid has the most common use in preparing useful fluorine compounds like Teflon (PTFE plastic), Freon (refrigerant), fluorocarbons and many other medications like the fluoxetine (Prozac). It has also got a variety of industrial purposes like the glass etching, metal cleaning and removing of rust. Moreover, one can also use it to clean silicon wafers in the semiconductor industry.

Health Effects

Hydrofluoric acid is an extremely corrosive liquid and a contact poison. It must not be ingested, inhaled or brought in contact with the skin as it will result in major poisoning. It can quickly penetrate the tissues and also permanently damage the eyes, lungs and mucous membranes. Further, when brought in contact with the skin, it will cause serious burns. Not only that, but one may also suffer from cardiac arrest and fatality. Even if you expose yourself mildly to it, you may get irritation in the eyes and throat, skin burns, bone damage and more.

Solved Question for You

Question- Hydrofluoric acid is used mainly to prepare which of the following?

a) Metal

b) Fluorine compounds

c) Medicine

d) Silicon

Answer- The correct answer is option B.

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