Ethanoic Acid (Uses) MCQs Quiz | Class 10
This quiz covers Class X Science (Code 086), Unit I: Chemical Substances – Nature and Behaviour, focusing on Ethanoic Acid (Uses), including topics like Vinegar and preservative-related (basic) concepts. Test your knowledge on its applications and properties. Submit your answers and download a detailed PDF of your results!
Detailed Educational Content: Ethanoic Acid (Uses)
Ethanoic acid, commonly known as acetic acid, is an organic compound with the chemical formula CH₃COOH. It is a simple carboxylic acid and is best known for giving vinegar its sour taste and pungent smell. Ethanoic acid plays a crucial role in various industrial and domestic applications.
Key Properties of Ethanoic Acid
- Formula: CH₃COOH
- Common Name: Acetic Acid
- Nature: Weak acid (partially dissociates in water)
- Physical State: Colorless liquid with a pungent, vinegar-like odor. Pure ethanoic acid is often called glacial acetic acid because it freezes to an ice-like solid below 16.6 °C.
- Solubility: Miscible with water, ethanol, and ether.
Primary Uses of Ethanoic Acid
1. As Vinegar
The most common and significant use of ethanoic acid is in the production of vinegar. Vinegar is typically a 5-8% solution of ethanoic acid in water. It is produced by the fermentation of ethanol (alcohol) by acetic acid bacteria (e.g., Acetobacter) in the presence of air. This process is:
CH₃CH₂OH (Ethanol) + O₂ → CH₃COOH (Ethanoic Acid) + H₂O
Vinegar is widely used as:
- A culinary ingredient: For flavoring salads, marinades, sauces, and various dishes.
- A pickling agent: Its acidic nature helps preserve foods.
- A cleaning agent: Due to its mild acidity, it can dissolve mineral deposits, grease, and grime.
2. As a Preservative
Ethanoic acid, particularly in the form of vinegar, is an effective food preservative. Its acidic nature inhibits the growth of many bacteria, yeasts, and molds that cause food spoilage. This property is extensively used in:
- Pickling: Vegetables (cucumbers, onions, carrots), fruits, and even some meats are pickled in vinegar to extend their shelf life. The low pH environment created by ethanoic acid makes it difficult for spoilage microorganisms to thrive.
- Condiments: Sauces like ketchup, mustard, and mayonnaise often contain vinegar not only for flavor but also for its preservative qualities.
3. In Industrial Applications
Beyond food, ethanoic acid has numerous industrial uses:
- Production of Acetates: It is a raw material for producing various acetates, such as vinyl acetate monomer (VAM), which is used in paints, adhesives, and textiles, and cellulose acetate, used in photographic films and textile fibers.
- Solvent: Glacial acetic acid is used as a polar protic solvent in organic reactions.
- Pharmaceuticals: Used in the synthesis of various pharmaceutical compounds.
- Rubber and Plastics: Employed in the manufacturing processes of some rubber and plastic products.
Summary Table of Ethanoic Acid Uses
| Category | Specific Use | Role/Application |
|---|---|---|
| Food & Beverage | Vinegar | Flavoring agent, acidity regulator, pickling agent |
| Food Preservation | Pickling | Inhibits microbial growth, extends shelf life |
| Industrial Production | Acetate synthesis | Vinyl acetate monomer, cellulose acetate |
| Chemical Solvent | Organic reactions | Polar protic solvent |
Quick Revision Points
- Ethanoic acid = Acetic acid = CH₃COOH.
- Vinegar is a dilute solution (5-8%) of ethanoic acid.
- It is a weak acid.
- Primary uses: Food flavoring (vinegar), food preservative (pickling), and industrial raw material.
- Its preservative action is due to its ability to create an acidic environment, inhibiting microbial growth.
- Glacial acetic acid is nearly 100% pure ethanoic acid.
Extra Practice Questions (Not part of the quiz)
- What is the chemical formula of ethanoic acid?
- Name two common household uses of vinegar apart from cooking.
- Why is ethanoic acid considered a weak acid?
- What is the percentage of ethanoic acid in typical vinegar?
- Explain how ethanoic acid acts as a food preservative.
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