Displayed Formula of Ethanoic Acid

Chemical Structure of Acetic Acid (Ethanoic Acid):

H    O
  ∥
H - C - C - O - H
      |
      H

Molecular Formula:

IUPAC Name:

Common Name:

Molecular Weight:

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1. What Is Ethanoic Acid?

Ethanoic acid, commonly known as acetic acid, is a simple carboxylic acid with the chemical formula CH₃COOH. It is the main component of vinegar (after water) and has a distinctive sour taste and pungent smell.

2. Structural Features

The displayed structural formula shows:

H    O
  ∥
H - C - C - O - H
      |
      H

Key Structural Elements:

Carboxyl Group (-COOH): The functional group consisting of carbonyl (C=O) and hydroxyl (-OH)
Methyl Group (-CH₃): Attached to the carbonyl carbon
Polar Bonds: C=O double bond and O-H single bond create polarity
Tetrahedral Geometry: Around the carbonyl carbon atom

3. Chemical Properties

Acidity: Weak acid with pKa of 4.76, partially dissociates in water to form acetate ions
Reactivity: Undergoes typical carboxylic acid reactions including esterification, amidation, and reduction
Hydrogen Bonding: Forms strong intermolecular hydrogen bonds, leading to higher boiling point than expected
Solubility: Miscible with water, ethanol, and ether

4. Common Uses

Industrial: Production of vinyl acetate monomer, acetic anhydride, and ester solvents
Food Industry: Vinegar production, food preservative, and flavoring agent
Laboratory: Common reagent in chemical synthesis and analytical chemistry
Household: Cleaning agent, descaling solution, and natural herbicide

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between ethanoic acid and acetic acid?
A: They are the same compound. "Ethanoic acid" is the IUPAC systematic name, while "acetic acid" is the common name.

Q2: Why is ethanoic acid considered a weak acid?
A: It only partially dissociates in water (about 1% at room temperature) due to the stability of the undissociated molecule through resonance.

Q3: What gives vinegar its characteristic smell?
A: The pungent odor comes from the volatile nature of acetic acid molecules that evaporate and reach our olfactory receptors.

Q4: Can ethanoic acid form dimers?
A: Yes, in non-polar solvents and in the gas phase, ethanoic acid forms cyclic dimers through two hydrogen bonds between the carboxyl groups.

Q5: What safety precautions are needed when handling concentrated acetic acid?
A: Concentrated acetic acid is corrosive and can cause severe burns. Proper ventilation, gloves, and eye protection are essential when handling glacial acetic acid.