Formic acid is the simplest carboxylic acid and popularly known as methanoic acid. This is not a very common chemical. It is having high acidic properties. The student will learn its nature and Formic Acid formula with examples here. Let us begin it!
Formic Acid Formula
What is Formic Acid?
Formic acid is a fuming liquid having the pungent acrid odor. It is systematically named as methanoic acid and its other names are carboxylic acids. This name came from the Latin or Greek names of their source. Formic acid and its salts are corrosive in nature and skin sensitizers. Its salt Sodium formate is mildly irritating to the eyes too. Some other popular names are Methanoic acid, Formylic acid, Ammonic acid.
Chemical Formula for Formic Acid:
Its chemical molecular formula is:
CH_{2}O_{2}
We can also represent it as:
HCOOH
Or  HCO_{2}H
It consists of a single carboxylic acid group i.e COOH attached to the hydrogen atom. Formic acid occurs naturally in some insects like ants and bees.
Preparation:
This acid is prepared through several routes in the laboratory. It is prepared by reacting sodium formate with the sulfuric acid. It is also prepared by the reaction of formamide i.e HCONH_{2} with sulfuric acid. Also, it is prepared by the hydrolysis of methyl formate i.e. HCO_2CH_3. These chemical equations are:
2 HCONH_{2} + 2H_{2}O + H_{2}SO_{4} → 2 HCO_{2}H + (NH_{4})_{2} SO_{4}
HCO_{2}CH_{3} + H_{2}O → HCO_{2}H + CH_{3}OH
Physical properties:
It is a colorless liquid in pure form. It is having corrosiveness and pungent odor. Its density is 1.22 gram per mL, melting point is 8.4 degree C and boiling point is 100.8 degrees C. Also, it is completely miscible with water.
Chemical properties:
It is a weak acid which behaves as a carboxylic acid with some aldehyde-like properties. It easily reacts with alcohols to form esters. Formic acid decomposes in the presence of acids or heat and produces carbon monoxide and water. In the presence of platinum, it decomposes to produce carbon dioxide and hydrogen.
Uses:
Formic acid is mainly useful as a preservative, antibacterial agent, artificial flavoring agent. It is also useful in leather tanning, dyeing, textile finishing, and rubber production. It is useful as a mixture with citric acid to remove iron oxide deposits. Also, it works as a reducing agent to reduce sodium and potassium dichromate.
Health effects:
Dilute formic acid is not toxic and hence is useful as a food additive. Inhalation of the fumes it can cause irritation to the mucous membranes. Also, its contact with skin may cause blisters or burns. Swallowing in large amounts may lead to kidney damage.
Chemical Properties of Formic Acid:
- Formic acid reduces mercuric chloride into mercurous chloride forming a white precipitate. The chemical equation is:
HCOOH + 2 HgCl_{2} \rightarrow Hg_{2}Cl_{2} + 2 HCl + CO_{2}
- Formic acid reacts with phosphoric pentachloride to produce formyl chloride, phosphoryl chloride and hydrogen chloride.
HCOOH + PCl_{5} \rightarrow HCOCl + POCl_{3} + HCl
Solved examples:
Q.1: Determine the molar mass of Formic Acid:
Solution: Its molecular chemical formula is:
CH_{2}O_{2}
Its molar mass will be:
= 12.0107 + 2 \times 1.00784 + 2 \times 15.999
= 46.03 gram per mole
Thus, molar mass of Formic Acid will be 46.03 gram per mole.
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