Methanoic acid (commonly called formic acid) has the chemical formula HCOOH (also written as HCO₂H or CH₂O₂). It is the simplest member of the carboxylic acid family, with just one carbon atom and one carboxyl group (–COOH). Methanoic acid is found naturally in ant stings, bee venom, and nettle leaves. Its IUPAC name is methanoic acid; the common name 'formic acid' comes from the Latin 'formica' (ant).
Methanoic acid formula: HCOOH (also HCO₂H or CH₂O₂).
IUPAC name: methanoic acid; Common name: formic acid (from Latin 'formica' = ant).
Simplest carboxylic acid — only one carbon atom.
Molar mass: 46.03 g/mol.
Stronger acid than acetic acid: Ka = 1.77 × 10⁻⁴.
Has reducing property — reduces Tollens' reagent and Fehling's solution (unique among carboxylic acids).
Found in ant stings, bee venom, and nettle leaves.
Used in leather tanning, textile industry, food preservation, and as an antibacterial agent.
Chemical formula: HCOOH (or HCO₂H or CH₂O₂)
Molecular formula: CH₂O₂ Structural formula: H–C(=O)–OH
Full structural representation: O ‖ H — C — OH
Key features of the structure: • One carbon atom (simplest carboxylic acid) • One carboxyl group (–COOH) — the acidic functional group • One hydrogen directly bonded to the carbon (unlike other acids where carbon carries other substituents)
Molar mass: 46.03 g/mol
The –COOH functional group makes it an acid. The H in –COOH dissociates: HCOOH ⇌ H⁺ + HCOO⁻ (formate ion)
Ka = 1.77 × 10⁻⁴ — stronger acid than acetic acid (CH₃COOH, Ka = 1.8 × 10⁻⁵)
Physical properties: • Colourless liquid with a pungent odour • Melting point: 8.4°C • Boiling point: 100.8°C • Density: 1.22 g/mL • Fully miscible with water • Corrosive — causes blisters on skin contact
Chemical properties:
Acidic nature: HCOOH → H⁺ + HCOO⁻ (stronger than acetic acid)
Reducing property (unique among carboxylic acids): HCOOH can be oxidised — it has an aldehyde-like reducing character: • Reduces Tollens' reagent (silver mirror test) • Reduces Fehling's solution This is because it can be considered as both a carboxylic acid and an aldehyde.
Reaction with Na: 2HCOOH + 2Na → 2HCOONa + H₂↑
With NaOH (neutralisation): HCOOH + NaOH → HCOONa + H₂O
Thermal decomposition: HCOOH → CO₂ + H₂ (with a catalyst) HCOOH → CO + H₂O (dehydration with H₂SO₄)
Natural occurrence: • Ant stings — HCOOH causes the burning sensation • Bee and wasp venom • Nettle (stinging plant) leaves • Some fruits (raspberries, strawberries) in trace amounts • Name origin: Latin 'formica' = ant
Industrial uses:
Homologous series (carboxylic acids):
The formula of methanoic acid is HCOOH (also written as HCO₂H or CH₂O₂). Its IUPAC name is methanoic acid; common name is formic acid. It is the simplest carboxylic acid with one carbon atom and one carboxyl group (–COOH).
Methanoic acid is also called formic acid. The name 'formic' comes from the Latin word 'formica', meaning ant, because it is found in ant stings. The IUPAC name is methanoic acid.
Methanoic acid (HCOOH, Ka = 1.77 × 10⁻⁴) is stronger than acetic acid (CH₃COOH, Ka = 1.8 × 10⁻⁵) because the hydrogen (H–) directly attached to the carbon in HCOOH is electron-withdrawing, increasing the partial positive charge on the –COOH group and making it easier to release H⁺.
Methanoic acid can act as a reducing agent — it reduces Tollens' reagent (giving a silver mirror) and Fehling's solution. This is unique among carboxylic acids because HCOOH has an aldehyde-like structure. It can be oxidised to CO₂ and H₂O.
Methanoic acid is found in ant stings (causes burning pain), bee venom, wasp venom, and the leaves of stinging nettles. Trace amounts are present in some fruits. This natural occurrence inspired its common name 'formic acid'.
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