[Chemistry Class Notes] Formalin Pdf for Exam

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 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 Chemical Properties

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

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

2HCHO + NaOH → HCOONa + CH₃OH

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

6HCHO + 4NH₃ → (CH₂)₆N₄ + 6H₂O

 

Uses of Formelene

• 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 sensitized individuals, despite being present at levels that are not usually considered dangerous.

• It’s used to create resins like urea formaldehyde and phenol-formaldehyde, which are used in foundries to make cores and molds.

• It’s used as a disinfectant, fungicide, fumigant, and preservative in agriculture and medicine.

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

Importance and Uses of Formalin

A carbon atom with an atomic number of 6has 4 electrons on its outer valence shell. So it can combine with many other elements and form different types of compounds. The number of types is so vast because carbon atoms can form chains by combining with each other. Hydrocarbons are the most famous among all the compounds formed by carbon. Hydrocarbons are the compounds formed by a combination of mostly carbon ( C ), Hydrogen (H) Oxygen (O), and some other less frequently combining elements such as Nitrogen (N), Sulphur (S), Phosphorus (P), etc. It is also interesting to note that because of such immense types of hydrocarbons found in nature and its importance in the working of nature these are studied in a whole separate branch of chemistry known as organic chemistry. 

In Organic Chemistry, we learn about different groups of hydrocarbons based on the type of bond they create while bonding with each other and forming chains. Examples are methane group, methylene group, methine group, etc. It also depends on the different types of substrates arched to the carbon chains. Aldehydes are one such group with Oxygen attached to one carbon atom at the end by a double bond. The first compound in this group formed by a single carbon atom bonded with two hydrogen atoms and one Oxygen atom is termed formaldehyde. It usually remains in a gaseous state at room temperature but can also be found dissolved in water. The water that contains dissolved formaldehyde is known as formalin. It is easily identifiable in laboratories due to its irritating smell or odor and is used as a disinfectant or germicide.