What is Formalin?

Formalin is another name for formaldehyde. Following a previous trade name, "formalin," "formaldehyde" was first used as a generic trademark in 1893. The simplest aldehyde is formaldehyde, which has the formula CH2O and is made up of hydrogen, carbon, and oxygen. At room temperature, formaldehyde is one of a wide group of chemicals known as volatile organic compounds, which evaporate and become gaseous.

Formalin Formula: CH2O

Formalin chemical is the first of the aliphatic aldehydes and is a reactive molecule. It's one of the most essential chemicals used in manufacturing. While formaldehyde is commonly thought of as a gas, it can also be found dissolved in water or other solvents which are known as formalin( formalin liquid). Formaldehyde is a naturally occurring compound that can be used in a wide range of products. This article will study formalin, what is formalin and formalin liquid in detail.

What is Formalin Solutions?

Formalin Composition

Formalin is a water-based saturated solution of formaldehyde gas. It contains about 40% formaldehyde gas (by volume) or 37% formaldehyde gas (by weight), as well as a small amount of stabilizer. The general stabilizer, in this case, is 10-12 percent methanol, which helps to avoid formaldehyde polymerization. Formaldehyde solution is very unstable without a stabilizer, and it appears to polymerize, forming insoluble macromolecules. Methylene glycol is the main product of the complete hydration of formaldehyde gas. Polymerization results in the development of paraformaldehyde as a result.

Formalin Structural Formula 

As we have discussed formalin chemical formula, given below is the formalin structure.

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Formalin Chemicals 


Formalin is a colourless liquid. Due to formaldehyde off-gassing, it has a strong, irritating odour. Since the PH of this solution is neutral, it can be used as a reducing agent to reduce other substances when making formic acid. Formalin solutions with a high concentration of formaldehyde are flammable. Since they can destroy dangerous microorganisms, this solution can be used as disinfectants and germicides. Aside from that, they have a dehydrating effect, the ability to preserve themselves, and the ability to combine with proteins, inactivating them and destroying cells. Formalin is widely used in aquariums to destroy parasites that live on fish because of these properties.

Synthesis of Formalin

  1. When formalin reacts with a base, such as sodium hydroxide, sodium formate and methanol are produced. The chemical formula is shown below.


  1. When formaldehyde reacts with ammonia, formamidine and water are produced. The chemical formula is shown below.

6HCHO + 4NH3 → (CH2)6N4 + 6H2O

Uses of Formelene

  1. Formalin solution can be used as a disinfectant because it destroys most bacteria and fungi (including their spores). Toxins and viruses are inactivated using it as an ingredient in vaccine production. In personal care products like cosmetics, formaldehyde releasers are used as biocides. They are known to cause allergic contact dermatitis in some sensitised individuals, despite being present at levels that are not usually considered dangerous.

  2. It's used to create resins like urea formaldehyde and phenol-formaldehyde, which are used in foundries to make cores and moulds.

  3. It's used as a disinfectant, fungicide, fumigant, and preservative in agriculture and medicine.

  4. A broad range of products, especially building materials, contain formaldehyde.

Did You Know?

Formaldehyde is a naturally occurring chemical that serves as an "important intermediate in the cellular metabolism of mammals and humans."   An adult has been confirmed to die after ingesting as little as 30 millilitres of a 37 percent formaldehyde solution. Other issues are linked to chronic (long-term) inhalation exposure. There are three key sources of formaldehyde emissions: thermal or chemical decomposition of formaldehyde-based resins, emission from aqueous formaldehyde solutions (e.g. embalming fluids), and formaldehyde output from the combustion of a variety of organic compounds (for example, exhaust gases). Formaldehyde can irritate the eyes and mucous membranes at concentrations above 0.1 ppm in the air, resulting in watery eyes. Inhaling this amount of formaldehyde may cause headaches, a burning sensation in the mouth, and trouble breathing, as well as a trigger or worsen asthma symptoms.

FAQs (Frequently Asked Questions)

Question: What is the Function of Formalin?

As formalin is dissolved in water, it is used as an industrial disinfectant as well as a preservative in funeral homes and medical laboratories. It's also a preservative in certain foods and products like antiseptics, medications, and cosmetics.

Question: Is Formaldehyde the Same as Formalin?

Formalin is another name for a formaldehyde aqueous solution, although the latter is preferred since formalin is still a brand name in some countries. Free formaldehyde is found in many disinfectants and antiseptics, as well as cosmetics, especially hair shampoos.

Question: Is Formalin used to Preserve dead Bodies?

Formalin is a type of formaldehyde that causes cancer in humans. It is a disinfectant that is widely used in mortuaries to preserve dead bodies and also in science labs to preserve specimens of dead animals.